I resigned properly but the old company holds my dues and visa cancellation

Dear Sir / Madam,

I am working in a Jebel Ali Free Zone company for the past 5.5 years.

Now I got a better offer, so I resigned last month and served 30 days notice period then handed over all my responsibilities.

I left there one week ago and still, the company didn't cancel my visa and they hold my settlement. Without a cancellation document, I am not able to join the new company.

Whenever I contact them they are saying different stories and keep my documents pending.

Please advise what to do.

Thanks,

J.