The email on your account is the key to both your 6-digit sign-in code and your login details, so it is changed by our team rather than self-service. This keeps your account secure.
To update it, open a support ticket in the help center using the Contact support button, ideally from the email currently on file if you still have access. Let us know the new email you want to use. Once we make the change, your next sign-in code and all your details will go to the new address.