That 'instruction' is incorrect - you log in with your PN account name alone
You can login with the default email address <accountname>@<accountname>.plus.com so the email is technically correct but using just <accountname> is simpler. In either case you need the account password
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
