I recently bought a starter for my truck on eBay and the seller shipped me the wrong one. Yes, I was peeved as it forced me to buy another starter locally at +$50 more (tying up $130 in operating capital in the wrong starter) and yes, I left them a real scorcher of a negative feedback. They did ultimately fix the problem and I did ask eBay to remove the feedback to neutral where I stated the issue and ultimate resolution - did this for an powerbook12 buy that took literally a month to get here as well.
With eBay being flexible about buyers requesting them help adjust feedback, I don’t really hold back if I feel it is warranted as it seems to help move things along for the better (in my experiences) on behalf of the buyer.
This however is my perception, so in the end I may just be creating more work for myself.

Still, it seems to me a good idea to explain the impact seller mistake/error has on Folks lives. Humanity is so often filtered out of online transactions, it’s easy to forget that your actions impact others sometimes in significant ways, so negative feedback still has value in that regard as well. If nothing else it is a training tool to understand why it is important to do better. Anyhoo my $0.02 cents.