The links are displayed in one line because of "white-space: nowrap;" style applied on "#footer .helpbox" element. However, removing the style makes the footer ugly as the theme wasn't designed to work with such long lists of foooter links.
You need someone who could tweak the X-Cart theme for you. Our team can do this too, you can contact them via the HelpDesk system at
https://secure.x-cart.com/