curl --request POST \
  --url https://demo.onlinebillingform.com/api/v1/vpn/connection/get \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --header 'token: <api-key>' \
  --data user_id=123 \
  --data server_id=123

{
  "status": true,
  "message": "VPN file successfully generated!"
}