Sorry this is happening to you, wook. I just went through the same kind of BS recently. Hope it turns out better for you than it did for me.
My tale of woe for sellers who still think Ebay has your back at all:
I parted out a a HT Hellboy figure into a bunch of individual auctions with BIN prices and the "make an offer" option.
One Buyer buys the HB Body straight up (which surprised me because I had priced everything high in the hopes of getting reasonable offers). He then proceeded to make offers on 8 other pieces. I accepted all of them and packed everything up nice and sturdy. Shipped Priority from NJ to NY.
Buyer contacts me stating the leg is broken off. I tell him to ship it back for a full refund. He says he doesn't want to pay shipping because he believes it was broken before I shipped. I tell him it wasn't - check my gigantic pic, check my 10 years of feedback, but I'm still willing to give you your money back, just return it.
He wants HALF his money back without returning the body. He threatens that he will leave me 9 negatives (1 for each piece) if I don't give him back half the price of the body.
I contact Ebay and the rep I speak to assures me that this is Feedback Extortion and once he leaves the negatives they will be removed and he will be penalized. She tells me not to respond to his future messages and gives me her name, employee number and tells me she has documented all of this.
A couple of days later he leaves the negs. I call Ebay. Guess what? there's NOTHING documented in my account. They refuse to refer me to the rep that I spoke to. Long story short, they tell me that it does not qualify as Feedback Extortion because the Buyer did not ask me for something that wasn't offered in the auction. In other words, it only qualifies as extortion if they ask for an additional item. Not MONEY. So actual extortion does not qualify as extortion.
Dealing with Ebay is like screaming at a series of brick walls. I now boast 9 undeserved negative feedbacks that I have no recourse against. My only consolation is that I didn't give in to this douche.
Checking his feedback left for others, I saw that he also left a neg for a seller because they wouldn't ship to him before his e-check cleared. Oh and his join date? January 2010.