With 79 feedback at 100% positive, I had one lady leave horrendous feedback, knocked me down to 98% in one fell swoop! Never asked for a refund, though I have a clearly stated generous refund policy.
I think EBAY should only allow negative feedback AFTER proof that buyer contacted or attempted to contact seller for satisfaction. IF none received, then post away.
The way it is now, anybody can just jovially go down the line and maliciously destroy an honest seller's business, like mine. If all they want is big-time powersellers, then so be it.
It's no longer worth the hassle here.