You listed a chip as uncirculated and the buyer emailed you to complain that the chip wasn't uncirculated and on the basis of that and that alone you have decided this guy is trying to switch chips on you?

That's a bit premature. Why not ask him to return the chip. You may very well find that he returns the same chip you sent and that you and he just have different ideas of what uncirculated and never saw table play means.

In fact looking at the scan in the auction it looks like the chip has a considerable amount of signs of use.