You can't change emails, you can't email support. I contacted them over a week and a half ago and they never got back. You can't disconnect and separate Google Login from the email even if they're the SAME email.
Trying the basic account with 1 email and then upgrading seems pretty common, but when I upgraded from personal to team, it doesn't refund the personal, and you get a free personal with teams, but then that email is already taken.