Instructions
Write down all of the information you need to pass along to the Xbox LIVE customer service representative. He needs to know your gamertag, your Windows Live ID, the telephone number associated with your billing address and the last four digits of your credit card number.
Call Xbox LIVE customer support. If you have any details about who may have hacked your account or how you think your information was compromised, this may be helpful to the representative. The situation around every hacked account is a bit different. Follow the representative's instructions carefully. Be sure to take her name. Ask if there is a specific number you can call to ask her any further questions.
Wait for Xbox LIVE customer service to contact you with your new login details. Sign into your account via the Xbox LIVE Billing Account page.
Type your updated email address into the appropriate text field. Click the "Save" button in the lower-right corner when finished.