ALWAYS, TAKE A PICTURE OF WHAT YOU SEND IF IT IS VALUABLE, AND ALWAYS PUT YOUR NAME, ADDRESS AND PHONE NO. INSIDE THE BOX WITH THE ITEMS BEING SENT, USPS or other. I did not do this and had a problem.
I sent a package, and something happened to the label, and I put clear tape over the label, after a several weeks it showed, as UNDELIVERABLE, sent to the Postal Dead Mail Center in Atlanta, GA. I had a tracking no. but no insurance.
I called the local Postmaster, and he said, to send him some pictures (jpeg), and he would forward them to Atlanta. It took 3 months, but they were still in the box, and were able to identify the goods from the description and pictures. Eventually they were sent to me.
I would suggest you go up to your USPS, and talk to the manager. Their system shows more information than we get to see. Plus, if it ends up in the Dead Mail Center, you have a good chance, by supplying photos, and a discription of the item(s) sent. You won't hear anything for several months so be prepared to wait.
I was told, they will not respond unless they find your package and contents.