As suggested by Mr Bahl you should use consumer protection act for the redressal of you grievance. RTI may not be of direct help in this case. Airtel being a private company, is not bound by RTI. But the other authorities such as TRAI and DoT are public authorities bound by RTI. Hence besides filing a case under consumer protection act you may also file complaints with TRAI and DoT. If they are inactive, you can activate them using RTI.