If you are not receiving emails from Supremacy titles, this may be due to a couple of reasons:
The email address on your account does not match the one you are expecting to receive emails on.
You may have unsubscribed from email notifications in the past. At this time, it is not possible to resubscribe.
Your inbox filters may be moving these emails to the spam folder.
You can check your associated email via the Account Settings menu, from the Settings screen.