Airtel — airtel deducting money by activating some entertainment plans on its own

On march 7th airtel had activated some entertainment plan without my knowledge. I was not aware of it until march 8th when i received their entertainment message. I immediately checked my balance and saw that ₹15 was deducted.
I spoke to the customer service person and he was saying that they cannot do anything since its been more than 24hours since the service has been activated..
This is a clear cheating done by airtel.. I did not get any message stating that a plan has been activated, else i would have immediately called them to deactivate it..