First, sorry to hear this. Rainphot's post, too. That shouldn't happen.
However, if you make this public you need to identify the seller. To warn others. To give him or her a chance to respond or make things right. Most importantly, because if you don't name the problematic seller, every past and present APUG seller becomes a suspect. This makes some people scared to buy anything. It creates a sense of insecurity about the classifieds. It isn't fair to the vast majority of people who sell and buy here, honestly and happily.