I've had 12 miners stuck in China UPS for past week as well, after a number of emails to and fro between myself and UPS and myself and Bitmain .. the latest response from Bitmain is:
Thanks for your consultation!
Chinese customs is very strict with Antminers these days. We are preparing the new documents they required recently. We will do our best to make the packages be released as soon as we can. Sorry again for this situation.
Please let us know if you have additional questions or concerns.
looks like a whole shipment from last batch release has been held up.