Airtel Prepaid
Not able to deactivate

This is guhan.

I have activated 60Rs sms pack on March 11. It will be active till may 10th.

But they have sent a message that after 60 days it will get automatically renewed..

If we want to de-activate, they gave a number to call *330*0# .

If i try to call that number, it says that " You are not allowed to call this number"..

Then how is it possible for me to cancel the auto renewal??

Kindly guide me through to proceed.