Hello!
I checked your listings on eBay, and I did see all 20 of your items in your store when I hit the "click here to browse all my eBay items!" link on your Scrolling Gallery.
As for the Scrolling Gallery itself, it is designed to only show 16 listing at a time. For more info and how to customize the Scrolling Gallery, check our help and FAQs
Hope that helps!