Forgotten email address can only be addressed by Funcom support.

You can try the forgot your password option and then enter the account name. It will send an email to the address on file but it does not give any clue what it is. For me, I got the email in 2 minutes.

Next check all your known email accounts inbox and spam folder. You can also a search on the ao account name in case you routed the email to a folder. The password reset link is only good for 24 hours but your really after finding out the email address.