Airtel — phone usage level is high, itemised bill wanted

i'm using the airtel landline phone connection for last 6 months, and i put on the one new connection, new connection bill is processed on the date of 20th of the month. first month bill hasbeen processed good. and next month bill is very high value amount of the bill but, usage is low, so, i want the itemised bill is also, but company collection exe. not response the complaint. i have don't pay the amount. now the time airtel company's new collection executive is torture of the payment.

please release to me. thanks