curl --request POST \
  --url https://sandbox-api.kotanipay.com/api/v3/withdraw/paybill \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": 500,
  "walletId": "5f9b2c7b9c9d6b0017b4e6b1",
  "paybillDetails": {
    "paybillNumber": "400200",
    "accountNumber": "ACC123456",
    "phoneNumber": "+254712345678",
    "remarks": "Payment for invoice #12345"
  },
  "callbackUrl": "https://example.com/callback",
  "referenceId": "PAYBILL-001"
}
'

{
  "success": true,
  "message": "Paybill withdrawal has been successfully created.",
  "data": {
    "id": "<string>",
    "message": "<string>",
    "referenceId": "<string>",
    "referenceNumber": 123
  }
}