Learned Experts/members have given valuable advice. Kindly follow it.
As advice by Mr. Vasudevan you may resolve the matter amicably with employer and obtain acceptance of your resignation, and subsequently work experience/service certificate, relieving letter, form 16, PF accumulation reports, NOC/NDC, FNF statement, payment of dues etc.
You have already sent an email and have put your employer on notice for going public and perusing legal route.
You may affirm to adjust notice pay as per terms of your appointment in FNF statement and supply you the FNF statement by redg. post and if any amounts are due and payable at your end as per correct FNF statement you shall pay the same by a/c payee cheque favoring the company. (Receipt of which shall have to be supplied to you by redg. post.)
Relieving letter is issued post all settlements. Other than notice pay you have to handover company property, I. Card etc which you may submit under proper acknowledgment. After this nothing should be due at your end.
You have caused abrupt termination and HR is following company policy and instructions as in your case. Be smart and obtain your documents from HR.
You should also retain the POD of PF forms submitted by you and try and obtain an acknowledgment from company. RPFC shall need concrete proof of delivery. Ideally company should attest the forms and submit to concerned o/o RPFC within 5 days and should supply the acknowledgment issued by RPFC to member. You may inform the company to supply this acknowledgment and all other communications by Redg. Post only.