It is not so easy for some time find the way to get help with problems. This support article should really be updated. But it's possible and I've tried it several times with success. Fill out the form using this link to Windows Live Hotmail E-mail Support.
Here are some other useful links:
Support for all of the Windows Live Services you find here like Windows Live OneCare, Windows Live Spaces, etc.
PS. There is even an Email Support Space for the email clients.