Internet service -poor service as well willful non disconnection

I was availing internet service from MTS. Due to their technical issues; I couldn’t able to get connectivity. Hence I have made several requests for disconnection but they couldn’t. I have stopped using facility and demanding payment for such service which was not working properly despite that, I have paid for charges more than six months from cancellation request. At present they issue notice sec 405,406 and 420 Indian penal code. I have proof of regular payment despite poor connectivity and several requests to disconnection of their service. They simply use tactics to extort money from naïve customer.