unfair means of balance reduction

Location/place: nagpur

Name of company/service: Airtel

last night i have checked my balance and it was 88 rs and today when i come to my office i seen again at 11 0 clock it is only 23 rs their were great mistake done by Airtel and they are not accepting that and wont refund my money back.
they are doing this every time by deducting balances by unfair means.

thank you