I've had the very same happen to me. I collect antiques and I spent 40 pounds (that's a lot for me) on two items. I didn't pay for 'insurance' as the seller was taking the piss charging a tenner for recorded delivery, and it was only two small photographs I was buying. I sent him a cheque and waited two weeks in vain before contacting the seller. He told me "I sent your items, but mind you, you didn't pay for insurance. Luckily for you I kept a proof of postage slip." and he sent me a scan....the idiot only wrote the wrong address down! When I told him this, he denied it by saying "Ok so I wrote the wrong address on the proof of postage, but I'm positive I wrote the correct one on the item."

I hoped that at the very least the photos would be returned to him, but when after two months, nothing happened, he refunded me 10 pounds, that's all. And a month later, the two VERY SAME photos were listed again!! Most antique photos have spotting and staining, and I know these were the same ones (my ones!) as I'd saved pictures off his last auction. The ******* didn't even have the courtesy to contact me to tell me MY photos had come back! He ignored all my emails. As most of you know, complaining to Ebay is a joke. All I got back were emails with links to their FAQs and similar bull shit.
I've been on the other side of the fence though too... I once sold a photograph to someone in Hong Kong (

) for 75 pounds, and highly reccomended he pay for recorded delivery. (And I wasn't conning him on the price either.) He told me it wouldn't be necessary as he'd been on Ebay for years and never had a problem. He paid me via Paypal and my husband sent the photo off the next day. (But forgot to get a proof of postage slip...whoops.) A few weeks later I get an email from Paypal to say that my account was being suspended due to a complaint from this guy. He didn't even contact me first, went straight to Paypal who of course wouldn't even give me the benefit of the doubt dispite being a loyal customer of theirs for years!! That really pissed me off. Anyway, this went back and forth. Paypal would only side with me if I phoned their number (in America!) and FAXED them a copy of the proof of postage slip (which I didn't have)... I could see Paypal wasn't gonna side with me so I tried to close my account down as I was not letting this guy get any money out of me, and I couldn't even do that. The guy ended up getting his money back (they debited my card) and Paypal closed my account as well as my Ebay account...the two are connected.
ALSO, (god, sorry this is so long!) once I won an item during one of Ebay's power outages. I'd put my bid in days earlier, and the site wasn't working during the last hour of the listing and while admittedly the picture was worth a fair bit more than I won it for, I won it fair and square. The seller said she got 5 complaints off bidders who had tried to bid on the item in the last few minutes but couldn't. I told her TOO BAD, they had all week to bid and it's their fault. It's against Ebay's policy to not sell an item to the highest bidder after the listing has ended. I told her this and complained to Ebay, but got no response. The woman listed the picture again a few weeks later and I was so annoyed that I made some bogus Ebay ids and really screwed her up. I actually did it on a couple occasions to her...she must have got so excited when she saw her pic go for thousands.......

I know that was bad but I had to do it!