HDFC Bank — Relieving letter not received on my mail id

Am an ex employee of hdfc bank (Emp code - 232848). I worked for 8 months there and left the job on 12 JUL 2020. I still haven't received my relieving letter and full and final settlement. It's been 4 months now. As many times i communicated with hr, he said that "i forwarded your mail, it will get processed soon" but that "soon" still has not arrived. I talked to ch as well and he is also procrastinating the matter. I am not able to join another company because i don't have the relieving letter.
These people are troubling me a lot. I am exhausted by following up in this matter daily.
I am in need of my relieving letter and settlement as i served this bank.
REGARD
RAHUL KHAJBHAGE
EMP CODE 232848