I had a terrible Mercari seller, too, that disguised a pony that had a chewed off leg. I still left them 3 stars but pointed out in the feedback that the lot was not as described. The seller, in turn, left me one star and threw a fit over my honest feedback. And because of that, I had at least one pony seller block me on Mercari, even though this person was the only person who left me anything less than 5 stars and they left it as retaliation. So, I don't shop Mercari much anymore.