Companies like YUMING when you ask them about your experts certificate will often deny knowledge of it which is an outright lie since it's inextricably linked with the process of getting your residence permit. As you will know you should have it in your possession, it even requires your signature, and there's a place for you to enter your next of kin and contact details should you be involved in an accident.

If you are on a plane and notice they have vacant seats in business or first class you are supposed to be able to claim an upgrade if you can produce your FEC. If you can prove you are a teacher by showing your booklet there are many concessions available to you. So, by Yuming illegally keeping your FEC they could be costing you money.

I have heard that another reason for the likes of Yuming in keeping your FEC is that they can use your name to buy things at a greatly reduced price. Yet another is about FT quotas.

Whatever YUMINGS reasons are [plain belligerence might be the main reason] for withholding your FEC it's all counter-productive serving to produce anger and mistrust right from the outset.