Airtel — airtel did automatic activation of value added services (vas) & deducted mobile balance

Airtel did automatic activation of value added services (Vas) & deducted mobile balance.
Airtel is continuously doing such frauds on customers & denying the fact that it has done on its own, instead trying to pass the blame on customer without any proof.
There are several complaints which has been lodged on forced activation of vas without consent of customer.
I need the answer from airtel why it has activated vas without my permission?