curl --request POST \
  --url https://openplatform.gateapi.io/payment/open/institution/v2/standard/order/refund \
  --header 'Content-Type: application/json' \
  --header 'X-GatePay-Certificate-ClientId: <x-gatepay-certificate-clientid>' \
  --header 'X-GatePay-Nonce: <x-gatepay-nonce>' \
  --header 'X-GatePay-On-Behalf-Of: <x-gatepay-on-behalf-of>' \
  --header 'X-GatePay-Signature: <x-gatepay-signature>' \
  --header 'X-GatePay-Timestamp: <x-gatepay-timestamp>' \
  --data '
{
  "prepayId": "35214673103159414",
  "refundRequestId": "202508271923022",
  "refundAmount": "0.018",
  "refundReason": "bourne-test"
}
'

{
  "code": "000000",
  "data": {
    "refundRequestId": "202508271923022",
    "refundGateId": "1991045981847818240",
    "prepayId": "35214673103159414",
    "orderAmount": "10",
    "refundAmount": "0.018",
    "errMsg": "",
    "orderCurrency": "USDT",
    "payCurrency": "USDT",
    "payAmount": "0.018"
  },
  "status": "SUCCESS",
  "errorMessage": ""
}