E-Bay needs to hear it direct from Buck. They don't care about anybody else's opinions on whether or not a knife is legit.
So, as Joe requests, report this stuff to Buck and there will be action. The bad guys often start three-day auctions on a Friday just to thwart attempts to get their auction cancelled.
And, of course you can't use the Buck trademark, but Buck clones have been sold for years and always will be. Older knives, as far as I know, usually lack patent protectcion. You can make an exact copy of a 110 and sell it, you just can't use the Buck trademark. Fortunately, Buck sells them so cheap that it's hardly worth it to sell clones.
However, there may be some exact copies out there marked with the trademark that are so good that nobody notices.