Airtel — Data cheat fraud

I am an airtel prepaid plan user. I have done recharge of 666 that gives 1.5 gb/day till 84 days. In that i use 850 mb but in my airtel app its showing i have use my full data. After that i ask their CUSTOMER care then they say i have used it and it was very rude. Due to some issue i have to add data so i recharge with 118 that gives around 12 gb but even though i only use 1 gb atmost but still it showing i have use 7 gb. You mean litteraly. Airtel doesnt give a ### about data fraud in open.