I have also received an unfair biased negative trust from this guy. What can I do? Nothing, as the BTC Talk account seller is more trustworthy then me in this community, as it seems 
Your negative trust was left a long time ago and this is the first complaint I have received about it. You were suggested to be used as escrow despite your lack of trust within the community, then when I requested a more trustworthy escrow be used the other party backed out of the trade.