I am kind of new here as well, so my opinion may not make much of an impression, but I think a big part of this deal is a persons personal perception of an object. I buy and sell a lot of knives at online auctions. I have bought knives that were described as "used" that looked to me like they were very much UN-used. I have also bought knives that were supposed to be Like New, but were most surely Very used. I have also sold knives that were used and described as such and had people say that the knife was much better than they thought it would be. It runs the gamut. In a trade, each person is looking to come out on top, or why trade at all. Not everyone will always be satisfied.
As has been said, pictures rule, and a calm head and being reasonable are a strong second. If things don't work out the way you want, well, then just buck up and accept it. Or don't trade any more. Life happens and it is way too short to make such a fuss about such a small thing.