The employer refuses to give a No Objection Letter. What to do?

Hi!

Good day!

It has been almost 4 years of working as a security guard in a Dubai-based company on a limited contract and recently I got a job offer overseas (Malta).

In order to get the visa, I need a No Objection Letter from my employer, which the employer rejected.

So, Is there any way to get NOC from my employer? Or does the MOHRE or Labour Court issue the NOC on the employer's behalf?