Would One Need To Continue Working Even After Serving The Entire Notice Period?

Being a professional, better if you drop an email mentioning all the details for your resign date and completion of notice period and ask for when they will be providing the relieving letter as well as FNF is a positive manner make sure to send it to your reporting manager, HR and and cc to your CEO. Wait for a couple of days and if you still do not get any reply then you can talk directly to your reporting manager and HR.

I have been communicated that my resignation has not been accepted. My superior is forcing me to finish some tasks which was not directly handled by me. Earlier, some other staffs of my capacity have been released, but I am being held back. What steps I should take in order to ensure a smooth handing over and joining my new organisation on time? My appointment letter states that " a notice period of 3 months is required from either end."

Dear Sourav,
Greetings!!!
Tell your superior directly that you have served your notice period and you are going to join a new company and you don't want to miss the deadline. Also mark a mail to HR department asking for relevant documents and proper handover. Don't forget to thank everyone before you leave.