The cheating you mention in relation to the original poster's example of barefaced refusal of a school to apply all the terms and conditions of the mutually signed employment contract is despicable.
There are laws in China to redress such fraud. The problem is they are seldom applied - there is no rule of law in many instances.
We can bleat about it till the cows come home, and thanks for being one of those foreigners prepared to do so. Though we can't stop the corruption we encounter, we can at least derive much satisfaction from bringing it to the attention of our fellow thread readers. Better to be forewarned, but even then one can be duped. I've identified the thieving school that is the subject of this thread. But for the sake of the original poster, I won't spell it out here at this point in time. I'm sure he'll do so after he's gone from there. On another board, there are some negative posts about it too!