curl --request POST \
  --url https://api.unibee.dev/merchant/invoice/mark_refund \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "invoiceId": "<string>",
  "reason": "<string>",
  "refundAmount": 123,
  "refundNo": "<string>"
}
'

{
  "code": 123,
  "data": {
    "refund": {
      "countryCode": "<string>",
      "createTime": 123,
      "currency": "<string>",
      "externalRefundId": "<string>",
      "gatewayCurrencyExchange": {
        "exchange_amount": 123,
        "exchange_rate": 123,
        "from_currency": "<string>",
        "to_currency": "<string>"
      },
      "gatewayId": 123,
      "gatewayRefundId": "<string>",
      "invoiceId": "<string>",
      "merchantId": 123,
      "metadata": {},
      "paymentId": "<string>",
      "refundAmount": 123,
      "refundComment": "<string>",
      "refundCommentExplain": "<string>",
      "refundId": "<string>",
      "refundTime": 123,
      "returnUrl": "<string>",
      "status": 123,
      "subscriptionId": "<string>",
      "type": 123,
      "userId": 123
    }
  },
  "message": "<string>",
  "redirect": "<string>",
  "requestId": "<string>"
}