Airtel — wrong recharge - not ready to refund

We tried recharging 1 number with 35rs to continue incoming calls. But they have deducted 3598rs and they are saying its our mistake itself. We entered 35 manually and we recharged through net banking. Its not a small amount. We shared our problem with collegues/friends and many of them faced the same problem. Airtel purposefully deducting our money and saying 'we cant do anything for this, you have selected your recharge amount'. Dont they have common sense to put 3598rs plan under 35rs plan. But the thing is we not even selected any plan just we entered the amount manually. Now, they are not even ready to provide the talktime or to refund the amount. Whenever we call them they say 'we cant help'.