Possibly stolen item in shipment to PSA

[mybestbretts]

On the 21st I sent an order to PSA via USPO. I tracked it and it
was delivered January 23. It was apparently refused by PSA and
I received an empty box back on January 25. Yes it was taped, etc.
I had packed the items in a padded mailer and placed it inside the box
with paper, bubble wrap, etc. Inside the mailer were 6 items, the order
slip and a money order. (Fortunately I don't put credit card information
on the order forms.) When I got the box back it had a couple of pieces of
newspaper and a little piece of bubble wrap.
I have filed a form with the Postal Inspection Service and the USPO.
I have checked with the bank and the money order has not been cashed
at this point.
Any other suggestions? I am now reading that the Bell Garden, Ca.
facility is the black hole of USPO and that's where all PSA items are
processed. Isn't that great.
I really want my items back not insurance.
Anything else I can do?