USPS tracking is the worst. I have been missing packages that they considered "delivered". They consider "mission accomplished even when delivered to the wrong house. My neighbor dropped it off over the weekend. I had one claim thru USPS that I eventually received payment for but it took a LONG time to get.
My friend is a driver for UPS and there is LOTS of parcels stolen and a few arrests were made from people following the UPS truck and picking up after drop off.
I hope you get your stuff or reimbursed.