I've changed the email on an old account before, not sure if you still can. I don't think Neo is a gp anymore, but he was the one who changed it for me, so I guess you need to ask a gp with the authorization to change your email.

If they stopped allowing this, my guess is because it's easy to steal accounts this way.
Maybe if you ask them to check which ips the account has been accessed with, and if it's only through one, then it might be easier to change the email.

You can try support.toonslab.com
Looks different from what I remember