Airtel — Inaccurate balance deduction

Call reference number :[protected] On 24th December 2014 I had a main account balance of RS 150 and a 3G balance of more than 100MB . During the internet session I did not recieve a notification indicating 100% data usage completion but post the internet session I was left with RS .03 on my main account and 35MB of data was still left on my 3G account. The airtel customer representative explained that post 90% consumption airtel checks wether multiple applications are using the internet data beyond the data balance and deducts from main balance without notification . How is it fair that I am charged from my main balance when I still have data balance left on my account? The senior airtel representative was very rude while explaining the same as if I was availing some free service from the reputed carrier.