Make sure you are logged in. On your profile page (click on your name in the upper right), there will be a link on the right side to "Edit my Email subscriptions." If you click on the link, it will generate an email to your current address on file. When you get that email, it will have directions on how to change your email address and other info.
If you can't get to whatever email account you have listed with us, then customer service will need to help you. The "Contact Us" info is available way at the bottom of the page under the "Help and FAQ" link.