How can I fix my order's billing information email?

Example scenario:

Q: Apparently the autofill form I filled out for order #xxxxx put in an incorrect email address. I fixed it in my billing information in my account settings, but it's still different from my order information. How should I go about fixing this? 

A: Your billing email address is stuck with your order, not your user information. Please open a new ticket in our Support Center to request a fix.