Airtel — activation of airtel masti pack and deduction of money without consent

I have received a message stating that 35 rupees have been debited from my account for activation of airtel masti pack on 2nd april, 2018. But i didn't opt for this service and this service has been activated without my consent. So i request to return my money as soon as possible and stop harassing people like this. I also request to deactivate this service as soon as possible.in future i would like to avoid this kind of harrasment. Please take the required steps in this regard.