curl --request POST \
  --url https://api.arcuserp.com/v1/returns/{id}/refund \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": 123,
  "payment_method": "original",
  "reason": "<string>"
}
'

{
  "data": {
    "return_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "return_number": "<string>",
    "amount": 123,
    "payment_method_type": "<string>",
    "order_refund_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "credit_memo_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "status": "succeeded",
    "idempotent": true
  }
}