Please be specific, as your accusations are not correct in my opinion. Throwing out random, unsupported accusations is insulting. Without specifics, you’re just throwing rocks.
Keep in mind that we are not directly involved in trades and any disputes are your word against the other guy. I myself and other mods have been involved in trying to mediate some disputes, including revenge feedback, but there is little we can do other than talk via PM to the individuals involved to try to come to some agreement.