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

{
  "invoiceId": "<string>",
  "refunded": 123,
  "status": "<string>"
}