What the client wants:
Build up an intermediary payment gateway to allow the agents to connect to the payment gateway through Web Services or API, from there, it can connect to the online payment services.
When a user makes a phone card payment, the card information will be sent to the payment gateway, then sent to the GSM devices for checking and payment, after that the results will be returned to the client. Agents can conduct tracking of payment information realtime/
PHP, Python, Bootstrap, Laravel, MySQL, jQuery, Web Services, Restful API