Always do a background check on anyone you trust with your accounts (or knowing the name of your accounts) or any payments that you give before you trade with them. As the above have pointed out there is an active report and you should always search to see if there is one first.
Generally you can either go one of two ways on Sythe. You can buy from a newer member and have a bigger chance of being scammed, but generally a cheaper service. Or you can go with someone who already is well known and has a good reputation on the site with many orders completed, and pay a bit more for the security that to them your order would be worth far more than losing their position on Sythe.
That doesn't mean that the biggest people on the site will never scam you, but the chances are certainly much, much lower.
If it were me personally I would not trade with an individual who has an active report against them. If they are banned and have no intention of returning they similarly have nothing to gain by holding up their end of the trade.