Like many others, I had the problem that the default administrator was "user" with an email of "firstname.lastname@example.org". I had done all the right things with the SMTP setup, but the request to change that email address never got responded to... but I chanced upon a workaround.
1) Having logged onto your WP instance with the "user" credentials, select "Users" from the dashboard and add in a new Administrator with the email credentials that you really want.
2) Log out of the WP instance and then log back in with the new Administrator credentials. This will ensure that the new account has been created properly.
3) Select "Users" from the dashboard and you will see two Administrators, the original "user" and the new account you are logged in on. When you mouse over "user", you will now see that it has a "delete" option. Use this and it will remove the default Administrator and leave you with just the one you want, set up with the correct email address.