I guess wait 10 more days but that's definitely lost altho you'll need to wait 30 days before USPS lets you file a claim, iirc. I recommend going to your local post office or the main one in your area and ask about it in person and see if that helps. Doing anything by phone is usually worthless from my experience.
See you guys say that it's lost, but here's the fun part. I once had an EMS package lost in the mail system before. They kept telling me I had to wait until the magic 30 day mark. So I waited until then and a bit more. Once I pressed them to move forward with filing a lost package claim, it magically appeared in Georgia. I live in Michigan, and EMS packages usually arrive / pass through customs in Chicago. So I don't know what to believe at this point. Mandarake was ready to give me store credit equal to the cost of the items + shipping though so I'm not too worried about it this time.
Edit: I have to mail some packages out so maybe I'll bug them while I'm there.