A pacs.004.001.09 is a Payment Return message, used by a financial institution to return funds from a previously received credit transfer (pacs.008) or direct debit collection (pacs.003). A return may be initiated by Mambu Payments following rejection by the creditor, or by the customer to return an incoming payment.

Mambu Payments supports the following return types:

Return of a received credit transfer (pacs.008)
Return of a received direct debit collection (pacs.003)

1. Message usage, definition and structure

1.1. Usage of a return of a credit transfer

--- Case 1: spontaneous return ---

pacs.008  →  [FI to FI Customer Credit Transfer]  (original incoming payment received)
                       ↓
pacs.004  ←  [Payment Return]                     (Mambu Payments returns funds)
                       ↓
pacs.002  ←  [Payment Status Report]          


--- Case 2: following a cancellation request ---
  
pacs.008  →  [FI to FI Customer Credit Transfer]  (original incoming payment received)
                       ↓
camt.056  →  [Cancellation Request]               (cancellation request received)
                       ↓
camt.029  ←  [Resolution Response]                (Mambu Payments sends positive reponse  
                       |                           to the cancellation request)
                       ↓
pacs.004  ←  [Payment Return]                     (Mambu Payments returns funds)
                       ↓
pacs.002  ←  [Payment Status Report]

--- Case 1: spontaneous return ---

pacs.008  →  [FI to FI Customer Credit Transfer]  (original payment order settled)
                       ↓
pacs.004  ←  [Payment Return]                     (Mambu Payments receives returned funds)


--- Case 2: following a cancellation request ---
  
pacs.008  →  [FI to FI Customer Credit Transfer]  (original payment order settled)
                       ↓
camt.056  →  [Cancellation Request]               (Mambu Payments sends a cancellation
                       |                           request)
                       ↓
camt.029  ←  [Resolution Response]                (Positive reponse to the cancellation  
                       |                           request received)
                       ↓
pacs.004  ←  [Payment Return]                     (Mambu Payments receives returned funds)

1.2. Usage of a return of a direct debit collection

pacs.003  →  [FI to FI Customer Direct Debit]     (original incoming collection settled)
                       ↓
pacs.004  ←  [Payment Return]                     (Mambu Payments returns collection)
                       ↓
pacs.002  ←  [Payment Status Report]

pacs.003  →  [FI to FI Customer Direct Debit]   (original payment collection settled)
                       ↓
pacs.004  ←  [Payment Return]                   (Mambu Payments receives collection return)

1.3. XSD definition and structure

The XSD message is available here.

A simplified structure is shown below:

Document
└── PmtRtr                                         ← Root: Payment Return
    ├── GrpHdr        [1..1]                       ← Group Header (mandatory)
    │   ├── MsgId                                  ← Message ID, text 1..35
    │   ├── CreDtTm                                ← Creation date/time, ISODateTime
    │   ├── NbOfTxs                                ← Number of transactions
    │   ├── TtlRtrdIntrBkSttlmAmt [0..1]           ← Total returned interbank settlement amount
    │   ├── IntrBkSttlmDt  [0..1]                  ← Interbank settlement date (optional)
    │   ├── SttlmInf      [1..1]                   ← Settlement Information (mandatory)
    │   │   ├── SttlmMtd                           ← Settlement method (e.g. CLRG)
    │   │   └── ClrSys    [0..1]                   ← Clearing System (optional)
    │   │       ├── Cd                             ← ISO code, text 1..4 (exclusive with Prtry)
    │   │       └── Prtry                          ← Proprietary code, text 1..35
    │   ├── InstgAgt      [0..1]                   ← Instructing Agent / sender (optional)
    │   │   └── FinInstnId
    │   │       ├── BICFI                          ← BIC of instructing agent
    │   │       └── ClrSysMmbId                    ← Clearing system member ID
    │   └── InstdAgt      [0..1]                   ← Instructed Agent / receiver (optional)
    │       └── FinInstnId
    │           ├── BICFI
    │           └── ClrSysMmbId
    └── TxInf         [1..n]                       ← Transaction Information (1 or more)
        ├── RtrId                                  ← Return ID, text 1..35 (mandatory)
        ├── OrgnlGrpInf   [0..1]                   ← Original Group Information (optional)
        │   ├── OrgnlMsgId                         ← Original message ID, text 1..35
        │   └── OrgnlMsgNmId                       ← Original message name, e.g. pacs.008
        ├── OrgnlInstrId  [0..1]                   ← Original Instruction ID (optional)
        ├── OrgnlEndToEndId [0..1]                 ← Original End-to-end ID (optional)
        ├── OrgnlTxId     [0..1]                   ← Original Transaction ID (optional)
        ├── OrgnlUETR     [0..1]                   ← Original UETR, UUID v4 (optional)
        ├── OrgnlIntrBkSttlmAmt [0..1]             ← Original interbank settlement amount
        ├── OrgnlIntrBkSttlmDt  [0..1]             ← Original interbank settlement date
        ├── RtrdIntrBkSttlmAmt  [1..1]             ← Returned interbank settlement amount (mandatory)
        ├── RtrdIntrBkSttlmDt   [0..1]             ← Returned settlement date (optional)
        ├── RtrRsnInf     [0..n]                   ← Return Reason Information (mandatory in Mambu Payments)
        │   ├── Orgtr     [0..1]                   ← Originator of the return reason (optional)
        │   │   └── Nm                             ← Name
        │   └── Rsn       [0..1]                   ← Reason (Cd XOR Prtry)
        │       ├── Cd                             ← ISO ExternalReturnReason1Code
        │       └── Prtry                          ← Proprietary reason code, text 1..35
        ├── OrgnlTxRef    [0..1]                   ← Original Transaction Reference (optional)
        │   ├── IntrBkSttlmAmt                     ← Original settlement amount
        │   ├── IntrBkSttlmDt                      ← Original settlement date
        │   ├── Dbtr      [0..1]                   ← Original Debtor
        │   │   └── Nm
        │   ├── DbtrAcct  [0..1]                   ← Original Debtor Account
        │   │   └── Id
        │   │       ├── IBAN
        │   │       └── Othr
        │   ├── DbtrAgt   [0..1]                   ← Original Debtor Agent
        │   │   └── FinInstnId
        │   │       ├── BICFI
        │   │       └── ClrSysMmbId
        │   ├── CdtrAgt   [0..1]                   ← Original Creditor Agent
        │   │   └── FinInstnId
        │   │       ├── BICFI
        │   │       └── ClrSysMmbId
        │   ├── Cdtr      [0..1]                   ← Original Creditor
        │   │   └── Nm
        │   └── CdtrAcct  [0..1]                   ← Original Creditor Account
        │       └── Id
        │           ├── IBAN
        │           └── Othr
        └── SplmtryData   [0..n]                   ← Supplementary data (optional)

2. Business logic

2.1. Return identification

A return is identified by the Return Information block inside TxInf. It must reference the original payment it is returning.

<PmtRtr>
  <TxInf>
    <RtrId></RtrId>               <!-- Return ID, mandatory, text 1..35 -->
    <OrgnlGrpInf>
      <OrgnlMsgId></OrgnlMsgId>   <!-- Original message ID, text 1..35 -->
      <OrgnlMsgNmId>pacs.008</OrgnlMsgNmId> <!-- Original message name, either pacs.008 oar pacs.003 -->
    </OrgnlGrpInf>
    <OrgnlInstrId></OrgnlInstrId>         <!-- original payment instruction ID -->
    <OrgnlEndToEndId></OrgnlEndToEndId>   <!-- original payment end-to-end ID -->
    <OrgnlTxId></OrgnlTxId>               <!-- original payment transaction ID -->
    <OrgnlUETR></OrgnlUETR>               <!-- original payment UETR -->
  </TxInf>
</PmtRtr>

Field	Tag	Required	Description
Return ID	`<RtrId>`	Mandatory	Unique reference assigned by the returning agent to identify this return. Text 1..35.
Original message ID	`<OrgnlGrpInf><OrgnlMsgId>`	Mandatory	The MsgId of the original `pacs.008` or `pacs.003` message being returned.
Original message name	`<OrgnlGrpInf><OrgnlMsgNmId>`	Mandatory	The message type of the original message, e.g. `pacs.008` or `pacs.003`.
Original end-to-end ID	`<OrgnlEndToEndId>`	Optional	The `EndToEndId` of the original payment transaction.
Original transaction ID	`<OrgnlTxId>`	Optional	The `TxId` of the original payment transaction.
Original instruction ID	`<OrgnlInstrId>`	Optional	The `InstrId` of the original payment transaction.
Original UETR	`<OrgnlUETR>`	Optional	The `UETR` of the original payment transaction, UUID v4.

Mambu Payments uses the same priority lookup logic as for pacs.002 to match a return to the original payment. See pacs.002 — identification of original payment for the priority table.

2.2. Returned amount and settlement date

Declare the returned amount and, where applicable, the settlement date inside TxInf.

<PmtRtr>
  <TxInf>
    <RtrdIntrBkSttlmAmt Ccy="EUR">1000.00</RtrdIntrBkSttlmAmt> <!-- mandatory -->
    <RtrdIntrBkSttlmDt>2025-06-01</RtrdIntrBkSttlmDt>          <!-- optional -->
    <OrgnlIntrBkSttlmAmt Ccy="EUR">1000.00</OrgnlIntrBkSttlmAmt> <!-- optional -->
    <OrgnlIntrBkSttlmDt>2025-05-30</OrgnlIntrBkSttlmDt>          <!-- optional -->
  </TxInf>
</PmtRtr>

Field	Tag	Required	Description
Returned settlement amount	`<RtrdIntrBkSttlmAmt>`	Mandatory	The amount being returned, with currency attribute (Ccy). Must not exceed the original settlement amount.
Returned settlement date	`<RtrdIntrBkSttlmDt>`	Optional	The date on which the return is settled between the agents. ISO date format.
Original settlement amount	`<OrgnlIntrBkSttlmAmt>`	Optional	The interbank settlement amount of the original payment, for reconciliation purposes.
Original settlement date	`<OrgnlIntrBkSttlmDt>`	Optional	The settlement date of the original payment.

2.3. Return reason

Declare the reason for the return inside the <RtrRsnInf> block within TxInf. Mambu Payments requires a return reason on all outgoing returns. <Cd> and <Prtry> are mutually exclusive — only one must be present.

<PmtRtr>
  <TxInf>
    <RtrRsnInf>
      <Orgtr>                     <!-- optional: identifies who initiated the return -->
        <Nm>Returning Agent Name</Nm>
      </Orgtr>
      <Rsn>                       <!-- only one of Cd or Prtry must be present -->
        <Cd></Cd>                 <!-- ISO ExternalReturnReason1Code, e.g. AC04, FOCR -->
        <Prtry></Prtry>           <!-- Proprietary reason code, text 1..35 -->
      </Rsn>
    </RtrRsnInf>
  </TxInf>
</PmtRtr>

Field	Tag	Required	Description
Return reason code	`<Rsn><Cd>`	Conditional	ISO ExternalReturnReason1Code. Mutually exclusive with `<Prtry>`. See common codes below.
Proprietary reason	`<Rsn><Prtry>`	Conditional	Scheme-specific or bilateral return reason, text 1..35. Mutually exclusive with `<Cd>`.
Originator	`<Orgtr><Nm>`	Optional	Name of the party (individual or organisation) that initiated the return.

Common return reason codes:

Code	Description	Definition
`AC04`	Closed account number	Account has been closed
`AC06`	Blocked account	Account is blocked
`AM09`	Wrong amount	Amount received is not the amount agreed
`CUST`	Requested by customer	Return requested by end customer
`DUPL`	Duplicate payment	Payment is a duplicate of another transaction
`FOCR`	Following cancellation request	Return initiated following a `camt.056` cancellation request
`FRAD`	Fraudulent origin	Fraudulent payment
`MS02`	Not specified reason, customer generated	Return by order of the beneficiary, no further reason
`NARR`	Narrative	Reason provided in narrative form via `<AddtlInf>`
`TECH`	Technical problem	Technical error in the original payment

2.4. Original transaction reference

Optionally repeat key fields from the original payment inside the <OrgnlTxRef> block. This allows the receiving party to reconcile the return without looking up the original message.

<PmtRtr>
  <TxInf>
    <OrgnlTxRef>
      <IntrBkSttlmAmt Ccy="EUR">1000.00</IntrBkSttlmAmt>
      <IntrBkSttlmDt>2025-05-30</IntrBkSttlmDt>
      <Dbtr>
        <Nm>Original Debtor Name</Nm>
      </Dbtr>
      <DbtrAcct>
        <Id><IBAN>DE89370400440532013000</IBAN></Id>
      </DbtrAcct>
      <DbtrAgt>
        <FinInstnId><BICFI>DEUTDEDB</BICFI></FinInstnId>
      </DbtrAgt>
      <CdtrAgt>
        <FinInstnId><BICFI>BNPAFRPP</BICFI></FinInstnId>
      </CdtrAgt>
      <Cdtr>
        <Nm>Original Creditor Name</Nm>
      </Cdtr>
      <CdtrAcct>
        <Id><IBAN>FR7630006000011234567890189</IBAN></Id>
      </CdtrAcct>
    </OrgnlTxRef>
  </TxInf>
</PmtRtr>

All fields within <OrgnlTxRef> are optional. Include as many as are available from the original payment to assist downstream reconciliation.