Airtel — Postpaid International Roaming

Airtel has an International Roaming pack with validity of one day (Rs. 649). I had purchased the same as I needed the service only for 24 hours after landing in a foreign location.
I received a bill where the same has been charged to me multiple times even though I had never requested for it. The total bill amount is 5772Rs. The phone was switched off and there was no usage in roaming from my end.
Upon inquiry the company representative is giving the reason that the pack automatically keeps renewing. However the terms and conditions on the website clearly says packs are not valid after validity period is over and will not auto renew unless requested.
Pls help in rectification as this company is charging on fraudulent basis in the name of postpaid and misleading the customer.