There are several possible reasons:
1) Because of your Email setting, the email with registration code went to Trash directly. Please check the Trash to make sure whether it is there or not.
2) Your Email service provider rejects Emails from unknown senders, so the registration code cannot be sent to you.
3) You provided invalid Email address when you ordered the software.
If you are under one of the last two situations, please contact our Support team at email@example.com to get assistance.