I don't believe in counter-positive feedbacks, but I know other DT members don't feel the same way. Maybe one of them might take pity on your case and counter Vod's negative. Good luck in any case.
As far as I'm concerned, both positives and negatives have waned in their effect: if someone trading with me is unwilling to actually go into the details of the trust ratings (incl. negatives) then that's not the kind of person that I would probably like to transact with. Where's the due diligence in "don't trust, verify" when it comes to the trust system? 
People who merely look at the numbers on your profile are most likely the same people that mainly look at the titles when they are constructing their reply to threads.
I would have used counters in the past but nowadays they are simply pointless.