I'd usually say you've got no case because Ebay. However, last week my partner sold a dress, the seller tried it on and started a claim stating it had been stretched and therefore was misshapen, she was generally quite unpleasant and arsy and has been messaging everyday since chasing her refund. We accepted the claim to avoid the hassle but the woman's attitude narked my missus so she phoned ebay, they stated that it wasn't even a valid reason to request a return so we needn't have accepted and also advised that we not refund and then when ebay take over challenge the buyer through that process. The guy went so far as to say that even if for some reason we lost the challenge we would win on appeal, and that he'd appreciate us taking this approach as it helps to identify problem buyers.
I think she's going to avoid the hassle and just refund though, the dress came back in perfect condition so she's only lost postage.