Speaking from the opposite view, I had 100% positive feedback as a seller. I sold a token for $5, a s the buyer said he did not receive it. He then immediately left me neg feedback. All the time I was in contact with him. After 2 weeks, to see of it was lost in the mail, I not only refunded his $5, but also his shipping costs. And he refused to retract his NF, after telling me he would! Sellers get burned as well. And you think ebay would do anything?!? They finally gave me his name and phone number, which I called......"umm, no one here by that name"!!! But did nothing to restore my unblemished account. Grrrrrr. Lol sorry for venting.
It doesn't seem like both are on a level playing field. Hence I only buy on eBay. I have one dealer who I sell coins to locally but most of my items I'll sell at the major shows. This seems to be the case especially with paper currency. I even buy more paper at the shows. I'm one who likes to physically look at what I'm buying when it comes to currency. Now exonumia is another story. EBay is much better for that.
That is totally mess up when the seller does that. I had some issues in the past about somewhat same issues. I bid on an item but the seller sent the wrong item and will not take back the wrong item. Another somewhat same issues. I had another seller who sent me another wrong item and I sent the msg to the seller that they sent me the wrong item and this item was worth more than what I've won and I offer that seller for more what it cost. The seller never respond and I got something else that is worth more. I think sometime they sell so much stuff that they don't realize that.
Ok call me lazy but they guy could be dead or hospitalized. It wasn't till after my dad died I found out he had been selling on eBay. All in all you should have your money back though. Good luck.