First of all,make sure that any contract you have signed is the official SAFEA one.Then,if an employer wants to get rid of you mid-contract,he will find it very difficult to do so,by using a scapegoat.
Bear in mind that the last thing an employer wants is intervention from Beijing by the independent tribunal in the case of a dispute that cannot be resolved.
If there are signs that you're persona non grata,watch your step from then on in,by adhering strictly to the terms and conditions of your contract.Virtually guaranteed you'll still be there when your contract finishes.Then move on with your satisfactory teaching reference.
What I have posted above doesn't just apply to black teachers, but to all teachers,irrespective of their skin colour.