I've sold a high end camera lens for my dad recently on ebay. This lens worked perfectly well, in fact my dad has exhibited some pictures he took using that very lens. Anyway about 18 days after a successful sale on which I was left feedback that said "well packaged, as described" etc. I've just received an email from the chap complaining that picture quality isn't very good. He says he's taken it into a shop and the bloke has found some fungus and dust (not that uncommon) in the lens. He is now saying that it was recieved in a condition not as descriped and wants a full refund!! My dad and me looked at the lens for dust as we knew this can be a common problem and we couldn't see any when we sent it.

Now my problem is all the feedback has been done, positive by both parties and he's now bringing this up over 2 weeks after the event. Does anyone have any experience or suggestions with this sort of thing?