Go to eBay.com
Click on the "My eBay" tab (log in if you haven't already).
Click the Personal Information link in the menu on the left under My Account.
In the Personal Information: section, you will see your "Registered email address" under "Email and Contact Information". This is the email address you need to use to check your order status.
Go to amazon.com
Click on the "Your Account" button located at the top of the page. You may be prompted to login.
In the "Account Settings" section, click the "Change your name, e-mail address, or password" link.
Your current registered email address information will be displayed on this page. This is the email address you need to use to locate your checkout.