Navigon no longer has any operations in the USA. You will have to try your luck with international support-- which has been hit or miss with users in North America.
And yet, they still continue to deceive the public by indicating they have an active location in the US and Chicago specifically. :twisted: http://www.navigon.com/portal/int/uebernavigon/unternehmen/standorte.html
I just got a reply back from navigon today