How did you pay for it?
I buy everything not face to face (that I can: some internet stuff with PP) with credit cards. Things that do not show up, or very much do not show up properly (wrong product, broken), and the vendor won't deal with it, you just call the card company.
They are quite surprisingly on your side, especially if you actually have been with them a while and pay your bill on time. I've never once had them (in the 3 times I had to do it) challenge me, or even follow up with more details. They apparently (from friends who have worked in the field) will pursue the case much like your insurance company will in a car crash. You get the money back, but then they bug the vendor A Lot to get their money back from them. And they have power as they can declare a business to be fraudulent and then no one will give them a card reader ever again. These days, that's a problem.
Also agree, especially in CA, that LE may be interested in this as it's lost Dangerous Stuff. Approach them nicely, questioningly, to see if they care or "want you to" file a report, not to demand they help as you are an aggrieved man. Not like you loosing a gun, so the S/N can get back to you so you have no functionally attachable liability, but I might pretend I had that concern as well; stuff I bought is just out there in the world, who knows what is being shot with it!