Airtel — cheating customers by not providing product benefits completely

Recharged a airtel three months pack of 2GB data/day, actually I am getting 1.5GB. Even customers care people doesn't solved my problem and in return each CCare person telling different stories. Even they don't know issue and solution for this. This is airtel customer care maintaining standards. I'm using my airtel sim from years, but I checked same way in other mobiles and found missing some data benefits. But now these great illiterate customer care staff certified that my mobile has some issue and some back ground apps consuming data that is invisible and some people said u r consuming full data but showing less in balance.
I'm not understanding what are these different answers for same issue. Where these people got trained. This is the way airtel maintain services to customers. No proper response and no valid resolution. Some times they put in hold for hours..