18-06-2021 12:18 PM
why am i unable to leave negative feedback for a Buyer?
Because over a decade ago eBay stopped sellers doing that as they abused feedback too much.
As proof eBay were correct - the false positives you left buyers for not paying is serious feedback abuse.
There's no feature to allow sellers to leave neutral or negative feedback for buyers, and it's against eBay policy to leave a neutral comment on a positive rating.