How to delete Kolab User properly

[User, Kolab]

Hi!

I added a user info at domain.com, then deleted that user via Kolab 
webadmin.
Mails sent to info at domain.com should now be delivered to an catchall 
account.

This does not work due to the reason, that these mails are delivered to 
the root user of the server.
(Mails sent to other Accounts which do not exist are delivered properly 
to catchall Account).

Now there seem to be some leftovers of the deleted info at domain.com user, 
so that mail delivery of mails to the catchall account does not work...

How to delete an kolab user properly?

Thanks in deed.