Timbo,

Read the disclaimer on the auction:

"Disclaimer:
We try to provide an accurate photo and description of the products we sell. Our goal is to have all our customers satisfied with their purchase from us. We will refund the original purchase price if not satisfied and we are notified within 3 days of receiving the item. Discounts due to dissatisfaction however are not offered. We reserve the right to negate auction results if in our opinion ebay systems or other unforeseen events limited the bidding process."

They offer a full refund if you are not satisfied.. so just nicely tell them how you know you will be dissatisfied because they are not Binions Horshoe chips and give them the link. It looks like an honest mistake by the seller and his disclaimer makes it clear that he wants satisfied customers.. I think if you contact him he will not hold you to the sale.