I don't think anyone here is able to find out and tell you which email addresses you own or use. To log into your existing account that is something you would need to know. Perhaps you can check each of your email servers and search the content for "wikitree".
You can contact email@example.com with your details to see if they can assist... they can if anyone can :)
If you so far have only registered for participation on G2G or did not yet do any genealogy, you might consider registering a new account with your accurate email address.
I hope this helps,