{
  "transactionId": "string",
  "amount": 25.0,
  "reason": "string",
  "refundType": "full | partial",
  "metadata": {}
}

{
  "statusCode": 201,
  "success": true,
  "message": "Refund initiated successfully",
  "data": {
    "refundId": "string",
    "status": "pending | processing | completed",
    "estimatedProcessingTime": "string"
  }
}

{
  "statusCode": 200,
  "success": true,
  "message": "Refund status retrieved successfully",
  "refund": {
    "refundId": "string",
    "originalTransactionId": "string",
    "amount": 25.0,
    "originalAmount": 50.0,
    "currency": "string",
    "status": "pending | processing | completed | failed",
    "refundType": "full | partial",
    "reason": "string",
    "initiatedBy": "string",
    "processedAt": "string",
    "createdAt": "string",
    "updatedAt": "string"
  }
}

{
  "statusCode": 400,
  "success": false,
  "message": "Refund amount cannot exceed original transaction amount"
}

{
  "statusCode": 404,
  "success": false,
  "message": "Original transaction not found"
}

{
  "statusCode": 409,
  "success": false,
  "message": "Transaction has already been fully refunded"
}