I managed to get around it for now.
Turns out if you change the user password, it resends another activation email with the new password.
Also I found out if you click the Mitel logo on desktop or double tap the logo on the phone app, you get the host/Username/PW prompts instead. From there you can log back in if you know your creds.
Figured I'd post the "secret" login method so the next person knows (or I forget and google my own anwser, haha)