If you sell something, and it's crap, or not quite as you have described, I will say so.
Two different sellers, two different e-markets.
Amazon seller sold a used CD. I had no problem with it being used, as the seller said it was in "very good" condition. It arrived, and the surface was obviously scuffed and scratched. I was able to rip the contents to my music directory, and with audio tools, remove the clicks and hisses. I gave her a 3 star rating. She kept sending me messages, claiming I had buyers remorse, and there was nothing wrong with the CD. The kicker is this: it got tapped by AQIS for having a foreign substance on it, and I took photos of the notice, the bright yellow and black AQIS tape, and the report. Sent them to her. She changed her tune, and said I was expecting too much.
eBay seller. I bought a silicone case for my S7. It arrived, and it was so loose and flaccid, my phone would fall out of it. I emailed the seller, included photos showing how it didn't fit on the phone. He offered me, I kid you not, 50 cents refund. "That is one helluva scam. You sell something for $5, and even with photographic proof showing it's faulty, this is your offer?" I reported him to eBay, and my money was refunded by eBay. I then gave him a neutral feedback rating, stating "Didn't fit phone, phone would fall out. Money refunded". Seller sent me a message, I am presuming is whining about the neutral rating, but tough shit. He was damned lucky he didn't get a negative rating.