Complain heavily to said Bureau, and I am sure they will phone the school and ask someone to come and see their office, and they will be asked a lot of questions they do not like. You could tell the Bureau you want another job because of contract breach, and they might help you to sort it out.

You've overlooked two important facts, which necessarily make your advice ill-founded. First and foremost, the wanna-be foreign teacher didn't arrive there with a signed and stamped contract. Last but not least, it's not the Bureau of Foreign Affairs in Nanchang's business to investigate complaints about claimed breaches of contract.
It must be stressed that anyone who takes such badly flawed advice will put themselves deeper into trouble. So, I advise you to keep your ill-founded advice to yourself from now on!