Best way to make members aware of someone ripping people off in trading section?

The seller hasn't been back to the site for a month. Prior to that he was an active member with all positive trader ratings.
OP Sonoramic reached out to me in a PM because I also was jipped by the same seller. I actually PM'd Admin (Joey) shortly after and he said there wasn't really anything admin could do about it and that the guy hadn't had any activity since so maybe there were unforeseen personal issues, etc. I was willing to give the guy the benefit of the doubt b/c obviously I couldn't verify either way. However, after several attempts at communication through the paypal provided email addresses the seller did respond 15 days after the payment had cleared saying the item had been shipped and he would get the tracking number for me. I said thank you and then waited patiently. A couple weeks went by so I kept reaching out requesting the tracking number and verification of the address he had shipped it to, but to no avail. Then finally after another 4 weeks (July 25th) his wife responded saying that the emails had been going to her junk folder and she was going to forward them on to her husband. Crickets yet again.