United States Post Office Broke property during shipping Nationwide

Shipping collectable coffee mugs home from college for my daughter. Purchased insurance as a precaustion. Had box stamped all over as fragile.  Mugs got broken so I filed a claim 2/10/14 on 2/21/14 they asked for photo's and it was approved on 2/25/14.  I was told a check was mailed that I never got because it was sent to the college in another state. After months of checking and doing what they told me to do, I was finally told that I had to send a written request for the check to be reissued, so I did on 12/3/14. Instead of my claim check I got an application to file a claim and start over. Now I no longer have the mugs that were broken (because my claim was approved and check on the way I didn't need broken glass any longer), the box that they were shipped in and the packing material are gone and now it seems so is my tracking claim and number from the post office website.  Everything is no longer available on the computer since my request for the check to be resubmitted. I can't reprint it, pull up the dates the claim was approved but thankfully I kept a couple of the original copies that prove it was approved and the check was never cashed. They refuse to help unless I have receipts of every Starbucks mug that was given to me from around the world from friends, family and my own travels. Who would still have that or who keeps a reciept for a gift coffee mug a year or more later? I hope someone can help get this resolved.