You should contact the SAFEA. You can quote the SAFEA guidelines directly to your employer.

Wrong way round!

You are obliged to approach your employer and draw his attention to contract breeches on his part. Then ask him to take immediate steps to resolve the situation. Have a witness with you when you do this.
Only in the event of you and your employer being unable to resolve the dispute should you approach SAFEA, and as a last resort.
At this point, bear in mind that a Chinese employer who feels he has lost face due to your actions won't have any compunctions to do the dirty on you by fabricating an excuse related to what you do in your actual job to fire you. Easy, he can tell you he's dissatisfied with your teaching, give you a week or so to 'amend' it, then say it is still substandard, and you're out the door. Of course, he'll have arranged your replacement to take over your teaching as soon as he's dumped you!
But if you're teaching illegally, the contract is necessarily illegal too. So, its terms and conditions don't apply at all. Therefore, SAFEA won't help you. In fact, they're likely to fine and deport you if they find out you're teaching illegally!