I did some trades with him multiple times without a hinge and I gave him a +rep back then, but now I'm changing that based on this experience.
In short: Back in August, he offered me a 12$ Green Man Gaming gift card code. I was skeptical, he never offered me a gift card for trade before and I didn't know GMG had a gift card for 12$. I asked about the source, and he gave me a vague answer about he reselling it. I asked about a price and we settled on 5 TF2 key. I was really surprised he accepted this for the code to be honest. After that I asked him to send the code first to test it, he acknowledge it, but went offline little bit after that. I haven't wrote him next day, but he did contacted me again later at night about another offer. I was interested in it, but I asked about the GMG code which we negotiated before and more about the trade. At first he didn't gave me any answer, so I called him out more and I let him know that I'm not mad about the code, but more about the whole situation. He told me he activated the code to buy something on GMG, but he didn't wanted to tell me what did he bought with it and he didn't wanted to show me any details he redeemed the code on GMG. I persuade the situation more to learn what really happened (which looks quite ridiculous from me), and later he started to beg me to forget about this situation, but the whole thing was just weird, so I let him know that I don't want to talk with him ever again in a later message and blocked him.
You can read the messages about the trade and persuading the answer here: https://imgur.com/a/HgjM0ot
I think if he really did a mistake accepting my offer, I gave him the chance to explain that and I would have accepted it and let it go, we all make mistakes, however that was not the case as you can see, but I really couldn't care about the whole thing... until now.
Today, one of my friend contacted me in his name and asked me, that am I still mad at him.
I wasn't mad back then, nor now, thank you for asking, but I told you that I want nothing to do with you, I especially didn't wanted you to involve more people to reach me about this long gone matter, but you reminded just today about it.
I should have wrote this rep before to let others know, this trader can be insensitive and inpatient, can spam you with his offers, even if you let him know you are not interested in it and he could be shady certain times.
True, I lost no items in that "trade" (nor I got any), but this situation is worth to let others know about this ordeal. This is not a revenge rep, if I wanted to do something like that, I would have already change this rep back in the summer.
-REP Be careful with this guy, he faked some trades with me and my friends so I blocked him on steam, then he ask for his friends for the last 5 days add me to bother me or for my friends talk with me about him, like "do u know omar? he said that he have your games for trade"...