Did you check the hk post site with the tracking number? If it displays a similar message, you can goto nearest post office and can track the pacakge post office location with their help.
There is chance they might attempt delivery more than once before leaving the notification card for self pickup
bwd, I know it was an attempted delivery because it said it was an attempted delivery at 4pm yesterday on the USPS tracking system because the addressee wasn't not home. What should happen is a card SHOULD be left after an attempted delivery. This didn't happen. Therefore I had no idea who to contact and where as USPS system doesnt provide those details.
What I did end up doing is going to the SYP post office with the USPS tracking page showing on my phone and my hkid card. They were very helpful and found my package. So I was able to collect it without the notification card. They did check my id and even called the contact number (my mobile) on the package to make sure it was my phone number.
The man helping me said I should be expecting a notification card in the next day or so and to disregard it.
Thanks again everyone - much appreciated!!