Very recently, I had a seller substitute an unacceptable coin. Their listing boilerplate is about six pages of rambling goofiness, and I didn't quite grok that the picture was "to show grade" rather than the actual coin for sale. The claim is rubbish regardless, the received coin was not a similar grade.
Fortunately, the seller offers free returns. In such situations, I am hesitant to choose a negative reason for the return, so I always choose Changed My Mind. I don't want sellers up in arms over criticism. For the same reason, I leave positive but vague feedback. Sellers get bent out of shape over neutral or negative feedback, and
ebay seems to delete non-positive feedback anyway.
How do you guys handle that situation when it arises?