Hi @kalelia, sorry to hear that you have faced this issue.
You already know that we have released a major update from our version 2.0.0 and the settings, subscribed users therefore are getting saved in a new way in the plugin to make the site faster.
However, we are currently running a cron job to migrate all the old data into our new format. The time required for this process may vary based on the amount of data.
So I would request you to create a staging that would be a clone of your live site and first there run the update and after a few hours check if all the settings, subscribed users are migrated correctly or not.
If you again face any issue there please let us know. We will assist you accordingly.