Unreasonable bill generated without the use of any services

Location/place: Dehi

Name of company/service: Airtel

I had been a user of airtel broadband services for about 2 years..my phone number was 01145657863..i had been having problems with the slow speed of the connection..hence i made a request for disconnection of the service in january 2013 and purchased tata photon..Since that day i started getting calls from airtel people asking me to retain my connection and the umpteen offers they will provide me if i do so..Fianlly after many days they told my mother to keep the connection on hold for 3 months for free so that if we want to reconsider our decision we can after 3 months..Since it wasnt causing any payment we agreed…However now after those 3 months they have denied any such offer made by them and have been calling us everyday for the past month and have charged us a bill of Rs. 2500..They refuse to accept that they made this offer and saying we need to pay for keeping the connection..And we have not even turned our modem ON for the past 4 months because we already had another connection.. These people call us everyday and trouble us and refuse to accept their own fault..As customers we trust the exececutives we speak to on the phone..We believd the offer made by the executive hence told them to keep the connection on hold.. But these people have misused our trust for making money by unfair means..When we havent used anything we find no reason to pay such a heavy amount..We are shocked at the change of behaviour of executives of the company who were pleading to get the connection restored few months back and are now not ready to accept their own fault..