Software to manage SIM Card Modem for Airtime Recharging through USSD Calls (RPA and AT Commands)

I need a custom Software to manage a Multi SIM Card Modem to recharge airtime to our customers. The main features are: [login to view URL] and read SMS from the customers; [login to view URL] the customers though M-Pesa payment API; [login to view URL] USSD Calls and follow the Menu to recharge airtime to the customers; [login to view URL] Process Automation to manage the sales; [login to view URL] programming with AT Commands. if you have any more questions you can ask and after you completely understand all the requirements of the project you can tell me: [login to view URL] cost to complete the project? [login to view URL]  [login to view URL] of work?  Just so i can have an idea and discuss with my brother