support@similarworlds.com
or write a ticket
https://similarworlds.com/support
Both are near the bottom of this page on "contact".
You'll need that particular email to your old account to access it. If this new accounts email is different you won't be able to use it.
There is no verified secondary access that I know of.
When you do access it you might be use the join account feature.
Yet you'll still need the passwords to the other accounts to join them.