Airtel — false billing for postpaid customers

Address:

400703

Last month even after not utilizing the data balance for airtel postpaid, airtel charged 500 rs for data charges. While looking at exceptionally high bill i checked the bill thoroughly and found that it is incorrect. After complaining at customer care they accepted the fault and told that it has been happening with all customers, but they did not do anything on their own and took action only after i complained.
This month also the same problem is happening with my bill and it seems that this is some trick by airtel, those who dont check their bill will fall prey to the situation.