Airtel — complaint regarding airtel service charges

Complaining about the bill discrepancies with airtel since 4 consecutive months. Despite complaint over call and mail every month they have been charging me additional rs. 80 in monthly bill for a value added service i never availed. On complaining they said its a technical issue and has been resolved but after that it happened again thrice. They refuse to check the bill before issuing. Though they have adjusted the money but this has been happening every month and is quite a harassment. Request help in resolving the issue permanently so that i don't have to check my bill and raise complaint month over month. Compliant raised earlier via email, trai and call. I am fed up and already looking for mnp. Ref no. For earlier complaint [|bal|ref60130939|].
First they claimed it's a technical issue then they said it's not their fault. Every month i hear a new excuse but no resolution.
Mails sent on 15 mar, 17 apr, 8 may, 10 jun