Hi how do I get unfair feedback revised?

[razorsedge361]

Hi how do I get unfair feed back revised have just sold an item buyer admitted it came fine but broke after they took it out of packaging i sent a message back saying I sent item off fine and was wrapped well etc never at any stage did the buyer say the item came damaged and etc in fact they said the item broke when they touched it with there finger tip lol after it was in the post for two thousand ks and lifted out of box then they brake it with their fingertip yeah right!!! anyhow so sent message back saying i wrapped it fine etc and was even tested before it was sent out and it is not the type of product that gets broken with your finger tip its a uhf  aerial sent in a pvc postal tube and wrapped in bubble wrap by the way anyhow i get a reply that your negged also low dsrd me across the board even though post cost me more than what I charged and left vulgar comments swearing on my feedback (not this profile) is there anyway I can get this revised also I had to open a unpaid item dispute to get payment initially so this may have something to do with it cheers any help would be appreciated