Hi lonestartrains,
I'm sorry to hear that this happened to you. In order for someone to have posted these listings through your Auctiva account, an unauthorized party must have gained access to your Auctiva log in information. We have seen a couple SPOOF emails going around lately that purported to be from us and were designed to steal the log in information of users, so it is possible you fell victim to one of those.
I see that you already contacted our customer support team about this earlier this morning and that is the best course of action under these circumstances.
If anyone else who comes across this thread encounters a similar problem, please contact our customer support team using the form on the following page of our site:
http://www.auctiva.com/help/requesthelp.aspx#-Mike