If you registered / signed-up and didn't get your registration / activation email then:
1. Check your spam or junk folder especially if you used Hotmail, AOL or Juno email.
2. Wait 30 min from your first attempt. After 30 minutes you can register again with same username. But this time use a different email address that's proven to deliver emails instantly. Like Gmail or Yahoo.com.
Eitherway you can always have them redirect email to your primary email address that you use now.
IMPORTANT: Read this ARTICLE to find out how to whitelist 110mb emails, so future important account related emails get delivered to your inbox. Else you could miss something and risk unexpected account deletion.