Create Refund

{
  "trxnRef": "trx_7ZP8X2",
  "amount": 500.0,
  "reason": "Customer returned the item"
}

{
  "id": "9f2a0a7c-0d4e-4d1e-bb0c-2b7f1c9f0a12",
  "trxnRef": "trx_7ZP8X2",
  "amount": 500.0,
  "status": 1,
  "reason": "Customer returned the item",
  "createdAt": "2025-11-15T10:05:00Z",
  "updatedAt": "2025-11-15T10:05:00Z"
}

{
  "code": "refund_not_allowed",
  "message": "Refund window has expired",
  "details": null
}