Hi Henning,
I would recommend that you create a staging site so that we can compare your live site and the staging site. This is is also very useful because we can test drive any X updates in the staging area, do the customizations and troubleshooting without disrupting your live site.
To know how to create a staging area, please check out these articles:
Once you finish, please provide us with your admin account/password and FTP credentials of your staging site as well.
Thanks.