I think lot of us are unclear on this so here goes:
I received 33 negative feedbacks from a non-paying bidder. Ebay DID NOT remove feedbacks and WILL NOT remove feedback. Only time non-paying bidder's feedback is removed is IF non-paying bidder has not replied to Non-paying bidder alert. As long as they do, even if it is to tell you to take a hike, they are entitled to post feedback.
If they don't reply, just PAY you and follow up with a positive feedback, ebay will remove THAT feedback.
So far I lost 3-4 positive feedbacks.
Your Power Seller feedback is not counted by number of users leaving feedback.(Percentage shown on your site) It is counted with number of negative feedbacks over number of positives. 33 negatives from one person put me in the 97% bracket and cost me my Gold Power Seller standing.
Oh well! Now I don't have to work so hard to maintain my position.