Please reach our support to change your account email. We would be able to provide a faster service if you share the email for change.
Please note that there can be only one main (account) email that allow to access our self-support service for making billing changes and downloading invoices. Billing emails though can be as many as you wish. Invoices are automatically sent to all billing emails after each (failed) payment made.
To get more details please follow the article: What can I do using self-support service?