Almost always, a termination is forever, I'm sorry to say.
You can use the Contact Us option (bottom of this page, right side) to ask Support for help. If it refuses your email (because you no longer have an account), try the old email address: firstname.lastname@example.org
OP really should check what the termination email said and then reply or contact the email address provided in that email. Going through this low level of customer service would only be a waste of time.