This is China, there are other english teaching jobs, n'est pas?

True indeed! No need to be a grovelling weasel nor a people pleaser, even if you're teaching with a 'dodgy' visa! In fact, the employer you're working for will accommodate your grievances in that case because he knows you know you can pull a runner whenever you choose, and leave him without a foreign teacher at very short 'notice', and there's no way he can make trouble for you with the authorities subsequently.