Obliging an employer to extend the notice period to handover work

Dear madam,

I am working in a private firm as an accountant (sales executive in the visa). My labor contract is limited. It has already expired on 06 Jan 2020 and my visa expired on 24th Feb.

I submitted my non-renewal letter on 28th Dec 2019 through the mail. After that, my company requested me to work till the end of Jan. Then they requested me to work till the end of Feb.

A few days ago, they recruited a new person and ask me to work a few days more to handover the work to him, otherwise, they will file a case against me and hold my final settlement until the handover is over.

So what should I do?

Kindly advise me!

Please!