I just had an issue that just about made me scream, but finally after about 10 days sanity prevailed and they removed negative feedback that a buyer unjustly left me. I had to keep after them by phone, however, which was really fraustrating.
I had an item up on eBay, and it sold to a buyer in the US. Right after the auction closed, he sends a message wanting to know what shipping service I would be using. When I responded, he responded with a "that's what I want" and that he "would be paying immediately and looked forward to me leaving him positive feedback." He didn't pay immediately, but did pay within a few hours and I shipped his item first thing in the morning.
About a day later I get a message from him asking me to "please do as requested." I wasn't sure what he meant, so I sent him a message that the item was shipped and if eBay hadn't forwarded him tracking info, let me know and I'd send it to him. Well, that wasn't what he was worried about: he wanted me to leave him positive feedback because he had paid "immediately."
Well, my policy is that I never leave feedback until the buyer has received his item and he is satisfied. Things got nasty then at that point. He accused me of making his feedback "hostage" and actually threatened to leave me negative feedback. I called eBay.
The eBay rep told me my policy was sound and that feedback is not required on any transaction, the buyer was out-of-line. I responded to the buyer and told him what the eBay rep told me, and told him he'd have to wait on his feedback.
The item arrived, and I get a message from him saying simply "Now lets see if you can do it." Well, I didn't respond immediately and a few hours later he posted negative feedback to my account because I was a "rude" and "cancerous" seller, basically warning others to "block" me. He never mentioned the item or its condition, however.
So... I called eBay again. The rep told me I had an obvious "feedback manipulation" case, and (supposedly) filed it for me, and told me the negative feedback would be removed following their "investigation" which would take "24 to 72 hours." That never happened. I called them about a week later, and the rep I talked to then could find no record of my previous call. So, we started the process again, only this time the rep said no "investigation" was needed, the buyer had obviously violated eBay's feedback policy. But... it still took them a couple of days to get the negative feedback removed from my account.
I was very frustrated over the process. IMO, given my experience as an IT guy myself, there is no excuse for something this simple taking so long. In eBay's defense, however, it was discovered that the buyer had changed his user-name at some point during this process and that may have contributed to it taking a little longer.
Anyway, I feel for you and hope nobody minds my "venting." But, you may have to get on the phone a keep after them...
Bill