I read somewhere in eBay's policies that if you give a positive feedback award but put a negative feedback comment, it will be removed and you'll get your wrist slapped. I think I have found a way around it. I received an unwarranted neutral (buyer didn't contact me about the problem so I couldn't sort it out). At the time, neutrals had just started knocking the seller rating percentage down, so I was rather dis-chuffed. I gave the buyer a positive and put in the comment,
'paid fast but DIDN'T CONTACT ME WITH PROBLEM. RUINED MY REP WITH UNFAIR F/B :-('
This was on 5th June and it's still there today (20th August) so hopefully, by putting something positive first, I might have got away with it.