I hate to be the bearer of bad tidings (and I sincerely hope this works out for you BigB1129) but I had a VERY similar thing happen to me in November 2003. I purchased a Glock upper assembly that was sent via the USPS with delivery confirmation, but no insurance. Well, it never showed up despite the "records" showing it was delivered to my house on a certain date and time. Where I live, it is also unlikely that someone would even know there's a package at my front door, let alone walk all the way to my door, up the stairs, across the porch and back down again. I filed reports with the Postal Inspector, the county Sheriff's Dept, etc... basically anybody who would listen. I made it very clear what the package contained so they knew what to look for (I even had pictures and a serial #). They asked the delivery guy and he "didn't really remember" but is sure he would have brought it to the right address. Well, it's now 14 months later and I've never seen the package, nor have I been compensated a dime for my loss ($300). The seller told me basically tough luck, he shipped the part, got confirmation that it was delivered to my house, so it was between me and the Post Office. Honestly, part of me can't blame him, except for not insuring the package, he did his part.
Anyway BigB1129, it's not that they're jerking you around because you're a 20 year old kid, they're jerking you around because they know that most people have little or no recourse against the USPS, right or wrong. It doesn't hurt to get the Postal Inspector's office investigating though, maybe you'll have more luck than I did.
Lesson learned the hard way, ALWAYS insure ANYTHING shipped by the USPS and insist sellers do the same for you, even if it costs you a few more bucks. One loss like ours basically wipes out any money savings accumulated by doing internet deals.
TO ALL SELLERS OUT THERE: In the interest of being a decent person, please spend a couple dollars to insure what you're selling if shipping via the USPS, even if the buyer doesn't pay for it. I doubt it will break your bank to do so and it will go a long way to prevent issues like this. To those sellers who don't, I think you're a bunch of cheap A-holes. To those who do, thanks.