unknown subscription

Location/place: bangalore

Name of company/service: tatadocomo

Hi I am using tatadocomo telecom service. they are subscribing the mobiles to some services without users knowledge and deducting money from the account. It happend twice in a week and they deducted Rs60 from my account. when I called the customer care they just deactivated without returning the amount and disconnected the call in between.
what should we do.