Reliance Communications — Harassment from Call centre team

I was using a Reliance data card connection from last 9 years or so. I had never switched to any other service provider. But finally I am now paying the price for being a Loyal (rather foolish customer). I had decided to upgrade to Wi-Fi connection of Reliance and hence taken a Wi Pod 2 months back. I had called the call centre to ask about upgradation. They said I can disconnect and take a new one. Hence is did that. Now I am using a new Wi-Fi connection. I have been getting disturbing call from the call centre team post that asking me to pay the bills of the old card. I have repeatedly told them that I have cancelled the old connection and taken a new reliance connection. Today one gentleman (mobile no: [protected]) calls me and threatens me regarding legal notice. When I tried to explain him, very rudely he tells that the call centre team might have give me wrong information and commitment. Well, that very weird way to handle a customer which I have not seen anywhere else. Also there was a month in which I was overcharged. I made a complaint and still it is not resolved. I never made it a issue later since it was petty. Now you guys are after me without any fault of mine. Please check earlier payment records and try finding out if there was any default made.