I worked in China for quite a few years and in my experience the majority of teaching establishments will give you a pack of old lies about one thing or another; however, Yuming really is the worst of the worst.

Even relatively not so bad employers will try and hang on to the 'expert's certificate' for reasons that differ, so,best-known to themselves. They shouldn't do so and it should have your signature in it- also there are pages that you are supposed to enter personal details, like next of kin and contact details; however, not worth fretting about.

I would hesitate to go and see the authorities yourself, Milo, unless you really have to. You have your residence permit, and to my knowledge unless you are caught working elsewhere, it takes the equivalent of a Chinese 'Act of Parliament' to have it revoked. I would just bugger-off. If you get a document from Yuming 'contract termination' something like that, do not sign it. In fact I wouldn't answer anything from Yuming-whether it be {e-mail, text, phone call, letter} nothing at all. These people are crafty and can get you to hang yourself. Silence is golden- they will not see reason, so don't try. You said you wanted to visit home, do that. Of course, if you don't want to go home, it's not impossible for you to get a position unofficially with another company(miles away from Yuming) until your present permit expires- not ideal but needs must when the devil drives. Countless teachers in China that have been forced into that situation when the job ends before time; not least of all because it takes too much cash to go home and return. Good luck.