First off take it with Support and not on a Forum post.
Second off.. you were the first to wrongly use a -rep to complain on his bad trading behavior but without having ever completed a trade with him/her. That's not how this works.. if everyone who didn't like how somebody else didn't accept the trade they wanted left a -rep this would be chaos.
As I said it was a Semi scam/ beware post. He did try to scam me twice during the trade, but he failed because I never traded with him. That is exactly what the Rep system is used for. To help protect the community from jerk traders that will try to scam them. Also I've never had to contact support before and have no idea of how to do so.
Use Support, and doesn´t Sound like a scam to me, changing minds and not accepting a offer is not a scam. Did he steal anything from you,has he given you a key which doesn´t work, did he give you phishing links? Than it´s a scam. If not...
He made offers without actually owning the items he was offering twice, He then tried to scam me out of the game entirely and when I told him plane as day, that he just tried to scam me. He laughed and said he was sorry and moved on to our 4th round of trade talks. The entire time I was open and honest about the game he was asking for and gave him the proper price of the game etc... The rules of -Rep is to post warnings of users that try to scam and or have scammed you. What you described are all scams that have happened and not the ones that fail when tried. I gave definitive proof of the entire trade on his steam rep page when giving him his negative rep. All I was saying in this post is that, should the staff of SteamTrades feel my screenshots of his attempts are not substantial evidence, then they can remove the -rep on his page as well.
Feedback should be used for :
Successfully completed trades.
Scammers/Impersonators and warning the community about those (this is what I -Rep him for)
User who left the negative feedback: http://www.steamtrades.com/user/Emdicox
The user who revenge -rep me is out of line and has tried to harm my business on steam. When I gave this user a negative feedback, it was for his horrific trade conduct and shady persona that caused me to hold concern for future traders as he attempted to trade scam me. When he failed he sought out another user to buy the game from at a price I offered him from the start of our conversation. The initial trade was 3 weeks ago and here are the screenshots.
http://prntscr.com/4os8jl
http://prntscr.com/4os8jl
http://prntscr.com/4os7ss
http://prntscr.com/4os7e5
http://prntscr.com/4os8ua
I still have no idea where I'd go to contact support, but everything is here. I edited the topic to include pertinent information.