It begs the question, why did you stay there as long as you did? If the conditions were so deplorable and the students were treated so caustically, why did you contribute to such a foul system by taking part in it?

Almost all private schools should be avoided. Do your research before coming to China. Be aware that there are professional organizations, especially universities, where your services would be quite appreciated. But don't fall into the trap of working for private schools until you've thoroughly researched the EFL scene here and are quite familiar with the pitfalls.

Finally, if you find yourself duped, don't hesitate to split the scene. Don't contribute to the mayhem by hanging out to finish out a contract that has absolutely zero validity anyway.