Consumer Redressal

Hi, I want to lodge a complaint against my telecom operator which is Airtel. I am currently having postpaid plan with airtel which gives me 1755mb of 3g data monthly.My billing cycle is 26to25 every month. Lately on 23April at 1.46pm I checked my data usage which showed 1647mb till 11.41hrs,23-april,2015. So Further I kept my data on to use upto 1755mb limit. But after sometime I received a message from the company that I have consumed 1813mb of data till 11.41hrs,23-april,2015 which shows I crossed my usage limit and charged me approx 200rs. How can it be possible that for the same time I used different amount of data?? I have attached screenshot of messages. Is it possible that at the same exact time I can consume different amount of data? Thay are just befooling customer to snatch extra money. Upon contacting customer care I received pathetic answer and they did not help me at all. They have charged me wrongly. Please help me. Complaint id is F1724565335. Thanks Gaurang Chavda