Unitech Group — Non-return of Fixed Deposit with interest from M/S Unitech Ltd.

I am a senior citizen, aged 83 yrs. I had deposited a sum in M/S Unitech Ltd. on 20.07.2013 at the rate of 12.5% interest for a period of 3 years, which had matured on 20.07.2016. I was getting monthly interest upto March 2015, subsequently from April 2015 I have not received the interest.I had sent letters to Chairman, MD's and Fixed Deposit division. But I didn't get any reply from any of them till date. I had also sent letters to various central government authorities like SEBI, NCLT, National consumer protection cell, Ministry of Corporate affairs etc., and finally I received a reply from Dy Registrar, Ministry of Corporate affairs stating that they had referred the matter to District and Sessions Judge, Dwaraka court (specially designated court) on 06.09.2016 for taking action. But I didn't get any reply subsequently. Recently I came to know that FD holders have to update all the details of the FD digitally. I have done the needful in April 2021. Now I am at a loss to know as to what more I have to do. Immediate response is highly appreciated.
Thanking you.