Airtel — treacherous balance deduction from prepaid account.

A service has been activated on my mother's prepaid airtel number for which they have charged rs 35 each week, so far 31 times. Which means they have simply deducted rs 1085 for a service i never activated, nor any permission was taken from me. And this is not the first time airtel has done this. It has happened to me on several occasions, as well as to my friends and family. But this time it was the limit. The number belongs to an elderly person who never realised what she is falling prey to. Suddenly the account balance became 0, which is when i started checking what has happened to the balance when she already has unlimited plans active. I need a proper channel to escalate the matter. Airtel has been subscribing bogus services on prepaid numbers, without their knowledge and permission.in my case, that bogus service was supermodelclub. Once this is settled, i will make sure i switch to a different network and never have to return to airtel.