Forcing an employee to pay visa costs in case of resignation before visa expiration

Hi,

In my offer letter, which I signed, it is written that the visa cost of AED 5000 will be incurred if the employee leaves before visa expiration.

After 6 months, I have given resignation with two months’ notice period according to my unlimited term employment contract.

Do I have to give AED 5000 as a visa penalty?

My boss says that he won’t accept my resignation until I pay the company 5000 AED. It has been 16 days since he didn't accept my resignation.

He is forcing me to give 5000 AED and threatened to ban me if I do not pay. Can I go to MOHRE?

If I launch a complaint to MOHRE and the matter is still not resolved and it is referred to the court, do I have to hire a lawyer then?