Hey,
In the event of a forgotten/lost/discontinued Email Address, you may log in via the website and select the 'Email Address' option to submit a request to change the Email Address that is currently assigned to the account. It is of utmost importance that the Email Address assigned to your game account is valid and accessible.
However, you will have to remember the answers to the security questions set during registration. If you have forgotten them, you will not be able to change your email.