Airtel — incorrect billing [protected]

Address: Mumbai City, Maharashtra, 400059

I am getting an incorrect bill since past 3 months. I have raised my concern twice to the contact center but again got an incorrect bill today. I have taken a plan of 399+ taxes but i am getting a bill of rs. 946/- where i am charged for services like sms which have been offered to me for free. The charges were waived off from past 2 months but i can't keep repeating my complaint. Need an end to this!