Subscribers list when the site is not connected to Mailchimp

Hello,

I wonder if there is a way to recover the subscriber list for those who signed in before I linked the Mailchimp account to the plug-in?

Do you think I can find somewhere in the database those names?
Or have they never been registered?

Thank you so much. Any help would be very appreciated.

The page I need help with: [log in to see the link]