Lets keep username's out of this for the moment.

I found it a bit hard to understand exactly what happened but it seems like you were expecting payment and didn't get it. Its important to always be weary of people you are dealing with no matter how nice they sound. When buying selling items anywhere (not just on forums) you should be carefull and the general rule is to not trust the other person for your own sake.

We will be looking into this further and one option is to find out who else a particular seller has dealt with and to get in touch with them to see if he/she is reputable or not. We might also be looking at implementing some kind of "Vendor Verdicts" forum or such for people to share their thoughts.