Videocon Mobile — Deduction of rent even if not subscribed for hello tune

Address:

Ahmedabad, Gujarat

Dear sir,
I got an out bound call from videocon for advertisement of hello tune. During the call I was given the instructions to press the relevant button to activate the service;however, i did not press any button as i don not want to subscrbe for any value added service. As soon as the call was ended, I got an sms that your service has been activeated and re 1 was deducted from my account.
When I called the customer care for the same an agent named Mamta told that i have pressed that's why the service was acivared. When I told her to transfer the call to the Supervisor, she, instead of transfering the call to supervisor, disconnected the call.
Sir, the question is here not for one rupee but the question is how they can activate any service without my permission?
Sir, please do needful because as i will recharge my account I will be charged for the remaining amount also for the same.

Your's trully,
Parimal G. Joshi