Airtel — high post paid bills mobile no. [protected]

I have shifted to airtel post paid plan of rs299 pm and well up to june 2017. July bill not send saying systems under problem and sent a bill for rs.954.26 in august. I paid the bill on[protected] promptly in good faith. Now a bill received for rs.962 and revised to rs.785 on my complaint. This amount is very high and as per my record i have to pay rs.80.74 only. The details are as under:

10.06.2017 paid rs.345 as per your bill. I. E. Bill of may
Payments due - june. 345
July. 345
August. 345
—
Total. 1035
Paid on[protected].954.26
Balance 80.74
My efforts with your customer care staff didn't yield any result and hence complaint.