Airtel — internet usage error

I have a plan of 1gb per day limit and i have app which moniters the network usage and balance. I have used 700mb but i couldnt connect to the internet after that. When i called customer care, they said me i have used 1gb data. This is totally unfair. Airtel started cheating its customers. Before some days i had another problem that is my plan is for 3 months but after 1 month they cancelled my plan, then i filed a complaint after that i got my plan back. I never suggest airtel to anyone and depromote it unless i get my internet usage back. This is totally not fair. We pay for your unfair words. Kindly solve this issue asap, thank you.