Bharat Sanchar Nigam [BSNL] — refund of security amount against surrendered landline

Address:

122018

The refund amount for my landline with broadband surrendered in april 2018 is not yet received till date. The refund amount is rs.1171.42.
A complain made to bsnl replies that the cheque was sent to my address & it did not came back. The address mentioned in my surrender letter was
H. No.1021, first floor, sector-31, gurgaon.
I never received a cheque in this address.
I demanded a reply from bsnl on this, but as usual they are not replying.
Regards.
Ajoy das