Airtel — more bill generated on postpaid connection

Address:

Hyderabad, Andhra Pradesh, 500049

I am using airtel postpaid connection since last 5 yeras onwards, they given credit limit 3600 rs, this month i. E september, they send bill amount 15797 rs.
So i would like complaint aganist airtel for making bill against credit limit and also for unused data (Internet). I was very tensed after seeing my post paid bill. Please do the needful help. I would like to attach my airtel bill, but am unable to attach.

My details,
B vijaya ramesh reddy,
Flat no:302, lotus leaf apartment, road no:05, hmt swarnapuri colony,
Miyapur, hyderabad.
Telangana-49.
Ph no: [protected]