Airtel — Forced into taking safe custody when I asked for disconnection.

I emailed Airtel 2 months ago to disconnect my broadband connection. They called me and asked me for a reason for disconnection and then forced me to move my connection to safe custody instead of disconnection. I explicitly asked and they confirmed that there would be no charges for safe custody. Now they keep sending me bills every month. When I called them to ask what the bills are for, they say that these are safe custody charges. I asked them why the connection wasn’t disconnected in the first place, and they said that they will disconnect it now. I haven’t used it in the past two months. I was forced to keep my connection and I was lied to about the charges. They didn’t hide, it they blatantly lied about it. What do I do!