Airtel — Not providing service

Hello,
I am tired of airtel. I took one number from airtel in January'09. my first bill got generated on 6th feb and due date was 24th. I paid my bill on 17th feb and then after every 10 days they bar my service and then calls from customer service centre people also dont attend my calls and people from their call center call me and talk to me rudely.
I being a working women have no help to follow up, still i went to their centres and tried connecting their nodal officer and all. they do not reply to me.
emails say call us on 121, when i call on 121 they dont pick the call. they have been harrasing me for past two months.
Please help me.