Please check your spam folder, or any other email addresses you might have used when buying your game. Sometimes when buying online, autocomplete might input an email address you don't use very often, so please check all your email accounts.
If you can't locate it, the most likely reason is a typo made in your email address when ordering, so please get in touch with our customer services team with your name, address, and the date you ordered and we can ensure your confirmation is resent to the correct email address.