This month's airtel bill includes two or three entries of dec30th broadband usage. Airtel claims that they missed out earlier these entries and hence included in this month's bill.Anyway I got a credit for Rs 4.33 ( which was in my free usage limit of Rs 560).They have no explanation how this could happen. When I asked whether we can expect old entries like this in future ,( as their billing system seems faulty) no reply. Chennai users check your bills.