Unless the Hong Kong website tells you the number is meaningless, there is little to worry about until at least December 15, about 20 days after shipping.
And given Christmas mails, Dec. 22 would be the earliest to actually start an Item Not Received Dispute.
Most of the numbers that eBay/Paypal gaily refer to as "tracking" are merely "delivery confirmation" and are not useful to the buyer. The seller needs to be able to prove delivery in order to defend an INR dispute.
And some are not even that. PP accepted the shipping invoice number Canada Post supplies with Light and Small Packet as evidence for the shipping requirements for Top Rated Seller status although it is not in any way tracking.