Can the employer hold my passport and ask for visa cost if I resign for salary reduction?

Good afternoon.

I am on an unlimited contract in Abu Dhabi, working at a private company. I've been here for 5 months, now I submitted my resignation letter to my boss last May 18 as he wanted to put me on commission-based payment.

I asked for a reduction of salary letter or any letter stating that I will be on a commission basis. He doesn't want to give me and wants me to reimburse the money he has put in my bank account. He wants me to pay for the visa costs. He is also holding my passport.

I have filed a complaint on MOHRE about this on May 18. Then he received a message about the complaint and instructed me to leave.

On May 19, I received a call from MOHRE and we settled and I withdrew the complaint. I went back to work to do the 1-month notice but he refused.

He is threatening me that I was absent since May 18. He doesn't want me to work there, he deleted my work email.

I was at the office on May 22 but he refused to accept me so I called MOHRE about my case and they reactivate my complaint again.