You can update your Endicia contact information and email address at Endicia.com. Please keep in mind that you have two Endicia accounts, each that will need to be updated.
To update contact information
Go to: My Account > Update Profile > Contact Information.
From there, update your address and email in the corresponding fields.
To update notification settings
Go to: My Account > Update Profile > Refund Notification Settings.
From there, you can update your email(s) or choose to receive summary notifications.