If you need to change your billing email address or mailing address because it has changed, you can do so in the Control Panel under "Update your Billing Information." In fact, if your contact email changes please please do make sure that we have your up to date email address.
Billing emails cannot be the email address that we run for you, for the simple reason that if we were to have a problem with your account, we would not be able to contact you if the only email address we had was the one having problems! Please make sure that you give us a REAL email address that you check frequently.
If you need to change your name, you can contact us, but note that it's really for internal company purposes only, so it doesn't matter much.
If you need to update your credit card information or payment information, you must do this through the PayPal account through which you are paying us monthly.