Hi Philip,
thanks for posting. Although I am not in Member Services, I'll give you some suggestions.
You should be able to change your primary email address via the website. First you will need to login. If you login here on the ACS Network, click on your name and select "Edit ACS profile" in the menu. That will take you the "MyAccount" application where you can change your email address.
Alternatively, you may access MyAccount, by going to www.acs.org and logging in there. The menu that appears when you click on your name should show a link to MyAccount.
The account overview on MyAccount should list your primary email address which you can change.
IF that is already correct and you are still getting some emails at the old address, try going to the email preferences page: THis is where you can opt-in or out of many of the ACS newsletters. This application allows you to enter email addresses other than your primary one for various newsletters.
If this is too complicated, i recommend you contact Member Services at service@acs.org and they can help you.
Christine