Airtel — bill generated of 3.8 lakhs

Address: Pune, Maharashtra, 411057

Hi, i have been using the postpaid connections since years and every time the subscriptions pack got renewed by its own or at least i receive messages for ending of subscription. I went to international roaming with 10 days of pack activated and was advised to de-active the pack otherwise it gets renewed by its own. After i came back to india, the bill generated is of amount 8.3 lakh which does not make any sense to me as my credit limit is of amount 1.5 k and i never receive any message that my subscription was stopped. Please help me to resolve this issue and clear the bill with including the subscription for 26 days