Airtel — unauthorised balance deduction of rs.150/- towards what mobile which I did not ask for

Today at 04.53 in the morning, Airtel has deducted Rs.150/- from my talktime balance towards WHATSMOB service which I never asked for. Though I complained to Airtel customer care, I was informed that they will not refund the amount of Rs.150/-.
Kindly take action on Airtel for deducting Rs..150/- from my balance talktime without my permission and also forcing me to use a value added service which I am not even aware of, nor am I interested in it.
Also take action on Airtel for refusing to refund my money inspite of my clarifying to Airtel executives of customer care that I do not want the service yet Airtel have deducted my talktime balance without my permission and knowledge.
Chitra