Race Space sends several kinds of email: tickets, receipts, wave times and race messages from the event organiser.
Check your junk folder first. That is where most missing emails turn out to be.
If it is not there, the email address on your entry is probably wrong or mistyped. Everything is still available in your account regardless.
Go to race-space.com and log in with the email address and password you created your account with.
Select My Entries from the main menu.
Every entry you have bought is listed there, along with the event communications attached to them.
From there you can download your ticket and receipt directly, so a missing email does not stop you taking part.
Fixing it for future emails
If the address on the entry is wrong, correct it using Edit Entry, covered in the article on editing your entry details. Emails sent from that point on will go to the right place, though ones already sent will not resend automatically.