Hi,
I do see many products on your link, and also in the categories of the sub menu "teile fuer audi".
If you still have a problem, please explain more precisely how to reproduce the problem.
Also, the problem is probably in the settings of the menu item, under the "categories options" or "products options" tab when you edit it via the Joomla menu manager.
So if you have the issue with a specific menu item, please provide a screenshot of the settings in both of these tabs for that menu item so that we can better understand the situation and tell you what it could be.
Also, when you make the screenshots, please try making them while logged in in English so that we can read them.