Airtel — wrong billing under data card number [protected]

Address:

Kolkata, West Bengal, 700001

Please note that on 20.09.2017 I had surrendered my above DATA Card through Airtel Customer Care Service over phone no.121. It was confirmed by the concerned officer over phone that my Data Connection will be disconnected with in 24 hours and upto the disconnection, a proportionate bill will be sent to me. Accordingly I had received a proportionate bill for Rs.2360/-( against my monthly rentals of Rs. 4000/- plus tax) under Bill no.[protected] dated 13.10.2017 and the same was duly paid by me on 27.10.2017 by cash. Please note that I have not at all used the DATA card from the date of surrender i.e. 20.09.2017.
From 1st week of January'2018 I have been receiving repeated phone calls from Airtel office saying that there is huge outstanding amount of around Rs. 14000/- and then I immediately wrote a letter to them on 15.01.2018 and informed that I had already surrendered my Data Card Connection on 20.09.2017 and upto the date of surrender I have cleared the amount of the bill on 27.10.2017. During last 2 months I have received a number of phone calls saying that around Rs. 14000/- - Rs 16000/- is outstanding. I have repeatedly clarified the matter but nothing has been done at their end.
I would request your good-self to kindly take strong action against the telecom company, who is deliberately harassing me inspite of the repeated clarification.