Frustration with delayed FNF and relieving letter process - Senior Associate EXL Service Employee Review

It has been more than 50 days since the last working day at EXL. However, with counscutive mails and tickets they failed to clear my FNF or sending relieving letter. They are not even reverting on mail, neither closing tickets raised by me. My current employer is asking me everyday for relieving letter,my job is now at risk. What to do..can't expect this from exl where I worked there for more than 6 years. Only remedy I have left to reach labour court bcz it's enough to wait for revert.