They simply **deduct** money from your pre-paid account.First of all it’s difficult to get in touch with customer care. If u get connected the hope-less customer care respond you with foolish answers..
They will keep you informing that you have activated so and so services and so your money is deducted. Even if they don’t have any proof and any confirmation from customer to activate any caller tunes like service.
Airtel is no.1 cheating and fraud company** and this is how they make money from deducting your hard earned money.Stay away from airtel if you don’t want your balance to get deducted for no reason.