Can an employee be charged for resignation during probation period?

Hi,

I joined a company in Dubai free zone 3 months ago with unlimited contract and a probation period of 6 months. My current situation is that I am not comfortable with my current employer and want to come back to my home country.

I have handled my resignation letter 10 days ago. My visa is still in the process of making and I have not got my passport back yet. The company does not want me to leave and now requires me to pay 30000 AED without giving any explanation.

Could you please let me know if Free Zone Labor Law allows a company to charge employee resigning from work during probation period? What is the process of resignation from here? When should company return my passport?

Regards,

Karolis Griskevicius