Always try to resolve these problems thru Ebay first. If the other party does not participate the resolution process Ebay will protect you against revenge feedback - they will add a note against the negative feedback and it will not count in your totals (but it will still be visible in the feedback comments).

This is pretty good step that Ebay has takes. But I do have a problem with their half-baked solution. If they have determined that one of the parties is not participating in THEIR OWN dispute resolution process they should block that part from posting any feedback for that particular transaction. Should be easy enough to do. I think active Ebay members should start pushing thme to do that. i send Ebay an email every month telling them they should do that.