Airtel — international roaming incorrect deduction

Address:

68==

Hi,
Recently my balance was deducted to 0, calming that i have answered a call for 13 secs and international roaming rental and call cost was deducted.

The phone was switched on and on table, no one was around it during the time airtel claimed the call was answered. There was a missed call (No received call logs) at the time airtel claims the call was answered. I have confirmed there was no voicemail or divert active on my connection.

The issue was raised with customer service and nodal officer and the answer was, as i have answered the call they are unable to do anything and closed the case.

It is clear that airtel's system did start the counter on detection.

How can i ensure this doesn't happen to me again? I am looking for an explanation and a resolution