There are a few reasons this might have happened:
- The email may have gone into your "spam email" folder. Check there first.
- Your email service provider may have a really strong firewall that is blocking the activation email. This happens occasionally. Contact your service provider.
- You may have typed your email address incorrectly - it's very easy to inadvertently use a coma instead of a full stop if you're in a rush. An accidental full stop or underscore can make all the difference in the world.