If you go through the main website instead of the app you can use "Eva" the online assistant to raise a dispute straight away. Just had to do it myself for much the same reason!
Oh wow, not come across anything like that being rejected on the Chinese side before. I was speaking to a Chinese guy who runs an airsoft store on Aliexpress couple of months ago, he said he was stopping selling anything like stocks, suppressors etc due to the problems getting them past Chinese customs. Looks like it's starting to filter down to single orders.