Mahanagar Telephone Nigam [MTNL] — Security Money Refund

Address:

Dilshad Garden

Hello, I m Deep Ram,
In August 2019, I have cleared all the dues of MTNL landline and disconnected the service. Till date (October 2020), i haven't got my security money refunded of ₹3000/- which they have promised to return within 90 days of the disconnection of service. Every time i call them, they asked me to wait for few more days. And at the end their number wasn't reachable. Please help me out in this.

My Landline Number is :[protected]
Place:- Delhi
Pincode :- 110093