My emoloyer is not clearing my F n F

Hello, My self Anirban Basu from Mumbai, i have joind my last employer on 3rd December 2019 as Project Manager and my principal work place was Mumbai, but my corporate office is in Chennai. After 3 / 4 months my CEO has started doing ill behave with me and started blaming me unethically due to labour issues at site. One i was returning home, he called me and started shouting on me and told me that i have been sacked with immediate effect. Next day i have got a call from the HR manager and she requested me to submit the resignation, which i have refused and also share the issues between my CEO and myself. Next day i have received a termination letter from the HR Department with fake allegations. After that, i have handed over all the office belongings properly. My last working day was 8th April 2019 as per my relieving letter. But still my employer has not cleared my f n f. Also i have the mail confirmation regarding my f n f from HR manager. I am in touch with HR department on regular basis through mail. Now they HR manager has given me a written confirmation to release my 8 days salary and other dues by the end of this month. Also the UAN no. I have received from the HR manager to withdraw my pf is not active. Kindly suggest what shall i do, if my employer will not clear my f n f by this month end. Thanks and regards Anirban Basu