Brian-
Caveat emptor.......
Make sure you send the chips back with delivery confirmation- this will prevent the "I never got them back" argument. But even though the chips were misrepresented (intentionally or not), you need to abide by the seller's return policy even though it may be quite frustrating.
Consider yourself lucky that it wasn't a high value item. This is one of the caveats regarding ebay purchases..."mint" is in the eye of the beholder. I think at the very least that ccgtcc members should try to accurately describe any damage or wear to chips they sell..I too have received "mint" chips that were table worn (but I ate the loss so as not to go through the same hassle you are now experiencing.) If in doubt, always email the seller for more information before you bid.
Gook Luck!
MP