Learned experts and members have given valuable advice. Kindly follow it.
From the day your resignation has been accepted the employer-employee relationship has ended.
The work experience/service certificate, FNF statement, relieving letter, settlement of a/c, payment of dues, form 16, PF accumulation reports are to be supplied by employer to you. From your side you should submit a reminder under acknowledgment, asking these under original seal and signature of the competent employee of the company,to be supplied to you at your last/current address by redg/speed post only, and no communication should be dispatched to by normal post/courier. Under the current situation you may even enclose a self addressed post prepaid envelope and mention that you are willing to supply the covers for future dispatch also if asked in writing. Once you have secured these documents you can feel relieved.
Although you are not liable for any punishment for unfair, illegal practices of your employer post your resignation, you may find your self entangled in unnecessary explanations.
The top management shall never agree that your signatures were forged and if the company is trapped by law enforcement agencies some executive shall be sacrificed.
However if you have decided that you want to end this nuisance you can lodge the complaint with competent authority to grant approval for medical seats, MCI that you have ended your employment on dated.............and you have are no way connected with any document bearing your name after this date. This shall set the ball rolling for exposure.