curl --request POST \
  --url https://api.paygentic.io/v2/invoices/{id}/refunds \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "reason": "<string>"
}
'

{
  "object": "invoice_refund",
  "id": "<string>",
  "invoiceId": "<string>",
  "merchantId": "<string>",
  "amount": "<string>",
  "taxAmount": "<string>",
  "total": "<string>",
  "currency": "<string>",
  "externalCreditNoteId": "<string>",
  "createdAt": "2023-11-07T05:31:56Z",
  "permalink": "<string>",
  "pdfUrl": "<string>",
  "reason": "<string>",
  "voidedAt": "2023-11-07T05:31:56Z"
}