Airtel — Hello tunes services

My AIRTEL mobile number - [protected]. This was taken during 2008. Since then having same "Hello tune". Every month amount of Rs.36 charged to my account. The last renewal of Hello tune was on 29.12.2015 and SMS sent for this. Today again one SMS saying your hello tune has been deactivated and call 543215 for activating hello tune. On contacting customer care, I was diverted to call 3 to 4 numbers (121 to 198, 198 to 199 and back to 121). Working in an office, it is really painful to spare time for this hello tune. There is no clarity at customer care, every person gives a different answer. But SMS keeps coming for having charged Rs.36/-. PLEASE REMEMBER, RETAINING A CUSTOMER IS MORE DIFFICULT THAN GETTING A NEW CUSTOMER. Hope there will be some response to this mail.