Dear Santu,
You please need not bother of any thing. in simple what I have understood is that your HR Manager does not have required knowledge in term of resignation and termination process.
If a company want to terminate a Employee then normally they ask for resignation letter and asked employee to leave fruitfully.
the other question is might be your management wants you to handover or KT process to take place.
you can just be silent, avoid gossip with your co worker.
once your KT process is over then they will do all the FNF process.
At last even then they have issue, please discuss in a pleasing matter as your carrier matters a lot.
Regards
Pandey
9840221925