Legal recourse available if PSU bank is not accepting resignation

Hi, I have been working for a PSU Bank in Delhi for last 4 years. I recently got an opportunity with a private NBFC and so submitted my resignation from the Bank. As per bank guidelines,a resignation cannot be accepted if any Disciplinary proceedings are pending. There had been a few NPA accounts, which i had dealt in d past, for which departmental inquiry was under process. And so, my resignation was denied till conclusion of staff accountability. I pursued the matter vigorously and got the matter decided. The process here is too slow. Finally, i was discharged from the disciplinary proceeding. Then i pursued for my resignation again. But, the is now on hold contemplating future disciplinary proceedings in some new NPA accounts. I have been following up since more than a month. Have also written to the top most authorities of the Bank. What are the legal recourse available.