Good evening Knud and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the Danish language being incorrect or incomplete,
I would love to help you with this topic.
The calendar’s language will follow WordPress’ language.
The level at which each plugin is translated can be found here: http://translations.theeventscalendar.com/projects
This is where you can also download the very latest version of your language file at any time.
Once that is done, you can simply overwrite the language files found in the /lang/ folder of both the Events Calendar and Community Events OR, as an alternative, put them in the /wp-content/languages/plugins/ folder.
Let me know if that helps.
Have a great day!
Geoff B.