You can do two border bounces - land crossings - in one year. You should be fine. People do them all the time. Just don't fly or go through Poi Pet, Cambodia.
Why did they have your passport? They were holding it hostage while you worked for them? Or were they in the middle of getting you an extension? It sounds like you two had a disagreement or you didn't show up to work. What happened for them to cancel it?