curl --request POST \
  --url https://api.withacclaim.com/v1/payments/{payment_id}/refunds \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": 50000,
  "reason": "Customer request",
  "metadata": {
    "custom_field": "value",
    "source": "api"
  }
}
'

{
  "id": "rf_AbC123XyZ",
  "payment_id": "pay_Def456UvW",
  "status": "Processing",
  "amount": 50000,
  "currency": "USD",
  "reason": "Customer request",
  "external_id": "ref_processor_123",
  "external_status": "pending",
  "metadata": {
    "custom_field": "value",
    "source": "api"
  },
  "created_at": "2025-10-08T18:20:31Z",
  "updated_at": "2025-10-08T18:25:00Z"
}