Hello,
1) Make sure that you are using the latest version of theme 6.3.5 and XStore core plugin 2.3.5.
2) Try to remove all the items, save the options and reload them. After that try to re-add the items and links.
3) If you still have the mentioned issue after these steps then provide us with WP Dashboard and FTP access to your site to check the issue in more detail.
Regards