My dear, ofcourse anyone can open a shitlist with any deal between 2 BHW members, even if the deal happened outside BHW. However, if people are quite happy with the deals, they would not open any shitlist (I feel sorry for you).
As usual, once again, you seem to be quite confused. I've never (upto now) had any marketplace thread at all whatsoever !!! Do one thing, ask any mod if I have ever had any marketplace thread upto now and I hope you would respect a mod's findings atleast.
And by the way what you are doing is hijacking threads and posting replies not related to the threads at all whatsoever. You or anyone is always free to have personal vengeances against any other member(s), but do not hijack threads for this prurpose, as it is against BHW guidelines. However, if you wish to continue doing so, please do go ahead.