Mahanagar Telephone Nigam [MTNL] — Security refund not recd

Address:

Borivali ( E ) , Mumbai - 400066

I have surrendered my Landline No # 28460338 on 1st September 2020 alongwith alongwith cancelled cheque.
I was informed that the Security Deposit Amount will be credited in my account.
Till writing this mail it has not been done.
Can you plesae expediate and confirm.