Airtel — giving less data

I recharged with ₹244 on 5 september which gives 1gb/day for 70 days +1gb/month.
1- they have not provided me 1gb data/day for 5 september
2 - i am able to consume max. 800mb data per day and they are showing that i have used 1gb. I have already called customer care and they are just saying repeatedly that i have used 1gb. But from 5 sept i know i could only use 800 mb. The calculation from airtel is incorrect and their data usage is showing wrong.