Because the feedback (perhaps rather cleverly) says "did not in my opinion decribe (sic) the item faults fully especialy (sic) what was important", it doesn't quite qualify for removal under 'normal" circumstances (if they had said "doesn't work" or similar, then I think it would have been removed immediately, but they're not contesting your description, just saying it wasn't good enough for some undisclosed reason). 

That's not to say I think the FB is fair or not (I'm not in a position to say one way or another), if there was some issue that could have been described in more detail then maybe, but if something doesn't work and you don't know why, your description says all you can. 

At any rate, the point is I think you would probably have better success at getting the neg removed if you used the defamation route: http://pages.ebay.com.au/help/community/defam-form.html