Hi,
I actually slightly disagree with you, giving full respect to the amount of time you have sold on ebay, I am a new seller just started roughly a month ago and I found this community court on ebay, where if you get a negative feedback, you can appeal in the consumer court and put your point across as in why you didnot deserve the negative feedback and if the jury which is a group of 21 buyers/sellers selected by ebay goes positively agreeing with you, the negative feedback will be removed. I think thats something you ought to try.
Warm Regards,
Akber Khan (sorry if this is not of use).