Would like to remove a domain from free email hosting

Would like to remove a domain from free email hosting

I created an account in March for a domain I really don't use for email, just to test the process. In control panel, I removed the email hosting (I think). Now I need to remove that domain so I can add in the one I really want to use. How do I do that? (and I need to do it by Monday night, May 4, so I can move the email from GoDaddy).

Thanks in advance