[Serusers] integration with prepaid Wi-Fi card

Hi All, I have built an ser server and offering postpaid voip right now. It's just a basic ser setup, authenticate then make calls then i bill them. But one client that offers Wi-Fi pepaid card would like to offer VoIP service using their card and he's going to use my system. My main problem is how to integrate it to their billing system. how can i do it in such a way that his customer can use my voip service and deduct the amount of usage on their Wi-Fi credit? And then I'll just bill my client for the usage of all his customers. hope my question was clear, thank you in advance. Regards Nhadie ________________________________________________ Message sent using UebiMiau 2.7