It's important for you to realize that if you are still in possession of your passport, it is probable that they have no intention of applying for your Z visa and plan on stringing you along as long as possible. In addition, it's doubtful that they are even a licensed school, so, if I were you, I wouldn't expect them to be applying for your work visa any time soon. This means: 1. You're working illegally. 2. You can probably leave without consequence because they've illegally hired you in the first place.

So, my advice is to take advantage of the fact that you have a place to stay when you move out of the apartment they've provided for you. Do not expect them to pay you what you're owed. Sever the relationship as quickly and cleanly as possible, but don't make any waves that could create a backlash for which you may not prepared. I assume you've still got plenty of time left on your tourist visa, so while you're staying with your friend search for a new job completely outside of Zhuhai. Don't accept employment from a private school unless you are absolutely sure they are licensed, and even then you must be very wary. Private schools generally treat FTs as if they are a dime a dozen; that is, along with being easy to scam, they're also easy to find. Unfortunately, they're right.