Here's a tip for you Tim. Don't believe what the auctions on eBay say, until you've checked. I've seen Rare, Scarce and Obsolete advertised on auctions of Common chips still in play.

Same chip that goes for $3 every day and you can get from almost any dealer, will sell for $22 if the seller hypes it and a couple of people bite and get into a bidding war.

Maybe instead of refusing to pay you can write the seller a polite note saying the chips aren't from the Horseshoe, as advertised, and you would like to refuse to buy them because of the mis-identification.

Then mention that they aren't even from the state as advertised...

Honey will catch more flies than vinegar.