I sell some stuff on ebay. a couple of times in the last month I've had buyers who have left neg feedback stating - "item arrived damaged'. which is fine as stuff can get damaged in the post.
I just don't understand why they don't attempt to reconcile the issue first. I'm happy to send a replacement at no cost. but they apparently have a broken item and I have their money. I don't see how it helps them.
the neg is soon swallowed up in pos feedbacks so that doesn't really bother me.
My guess is your selling something really cheap and the effort required to contact you and get sent another one outways the value of the item itself and the easiest way to get some form of redemption is to leave you a neg.