If you have not received your welcome email, simply send us an email at billing@superb.net. Please include your order invoice number (or domain name), and be sure you are sending the email from the address we have on file. If not, let us know so we can assist you faster.
If you can log on to myCP (http://mycp.superb.net/) with your domain name and password selected during your order, you should be able to reset any other logins there directly, which may be more convenient if you need access immediately.