I know this is a long shot but there is a vendor that I purchased something from that I do not remember the name of and what I purchased has missing parts. All I can tell you is the product is one of those laser cut dice boxes with d20 engraved on the locking mechanism/lever. I purchased the one where I need to assemble it myself, it came in a plain brown envelope with no markings on it whatsoever. This product was not one of their normal products and was a test run to see if they would sell. 

The part I am missing is the back piece to the box.  

Anyone have any ideas?

Can you check with your credit card company to see who made the charge? They may be able to provide contact information for you.