Airtel Exess Billing

In september last year I recieved an exess bill from airtel and when I called the customer care to ask them about this they did not give me a proper answer and so I did not pay the exess bill. In August I had also called the customer care to activate a 1GB 3G pack for Rs. 300 and I had told the person to activate this plan only for 1 month. To be sure I called next month and again told them to de activate the pack and they said they will do it. But they did not de activate the pack and charged me Rs. 300 for 3 months straight and the funny part is I rarely got 3G speed here at my home, Most of the time I got very slow speed which was actually even slower than 2G and now they're making me pay for 3G speed. Other than all these chares they have also included some other internet charges which might not be true because I had a free 2G pack in my monthl plan which was still running and not over. I will also not pay the late charges of Rs. 200 since they were the ones who made this problem. Im not sure about this but another thing is they are asking me to pay for October but as far as I remember all my outgoing services were blocked on my number in October so why should I pay for October. Since the last six months I have been after them trying to reach a solution but no one is helping me. Last month I called them and offered them to pay about Rs. 1400 which my actual bill should be and I also said that I had told the customer care to de activate the pack but they said that I did not give any such request for de activating the pack and that my number has been dis connected now so they cannot make any adjustments and they want the full sum of Rs. 2600. I told them this is not fair and I will file a case in the consumer court, They said I can do whatever I want. Now since the last month they are harassing me by making an advocate call me saying Airtel has filed a case against me and that I have to go to the court with my lawyer. They keep harassing by calling again and again due to which I have to keep my phone switched of. Please help me with this.