Welcome to Auctiva. Your current listings have actually not been removed from eBay, but are just being “re-indexed”. When you sign up for Auctiva and the scrolling gallery is appended to your active listings, eBay must "re-index" your items to appear in the appropriate search results pages which, according to their help page, can take up to 6 hours.
Additional information on this fairly common eBay issue is available on the following page of eBay’s help index: http://pages.ebay.com/help/find/questions/wheres-my-item.html
. If you have any further questions about this specific issue, I recommend you contact eBay’s customer support department.
If you have any additional questions or concerns pertaining to your Auctiva account, please contacting our customer support team using the appropriate link on our help page: http://www.auctiva.com/free-auction-software-help/help.aspx