Useless charges applied on postpaid bill

Since 8 months i have to adjust unnecessary charges added to bill continuously. Airtel service provider is worst in service. I took two postpaid card with same alternate number. Everytime bill amount increased and charged and for the same call and make them to solve. So to avoid all the callings i stopped using one of postpaid card and didn't even paid last bill because of such worst service. Now they even affected the sevices on my number also.
I am even ready to pay the bill but they arey charging amount rs.2900/- and the actual usage bill is 352/-. Why i will pay extra charge for which i have not used.