Mahanagar Telephone Nigam [MTNL] — even after connection surrender - bills follow & paid by yes bank bill pay

Address:

New Delhi, Delhi, 110085

Mtnl phone number[protected] in my name renu jain was surrendered on 31 jan 2017 - instrument etc deposited in rohini office.
Still they sent bills & paid by yes bank bill pay system for 3 months about rs 976.
Later, i visited again & requested for refund in may 2017.
Today received a cheque of rs 816
(Security 1000 - 184 debited?)
Hence 184 + 975 paid in excess = rs 1160
Still outstanding with mtnl, withheld unnecessarily. Please arrange to look into account & refund accordingly.