We too hope you get "speedy" support! You did submit a Support Request via the control panel, right? These are customer-to-customer forums and, while they occasionally pop in and look about, DH staff generally does not post in these forums, and this is not a way to contact them for support.
While you are waiting for a reply, it sounds like your "news" email accounts may not have completed the "creation" process. It takes "a while" for a new email account to be completely setup, and the amount of time seems to vary a bit (possibly depending upon how the new account creation process is processed).
You might also try using both the "firstname.lastname@example.org" and just the "emailusername" form of the login, to see if that makes any difference (given recent DNS change).