We never read the content of any of your emails but we do have access to some metadata - information about an email which you don't usually see.
This metadata tells us if the email has an unsubscribe link or instructions on how to unsubscribe, if it does then we show it to you in Leave Me Alone for you to unsubscribe from.
Sorry, we can't subscribe you to a mailing list you have unsubscribed from. You'd need to visit the website for that mailing list and subscribe again manually.
During onboarding we asked what we should do with the emails you unsubscribe from. One of the options was move these emails to a folder. You can check if you have this setting enabled and the name of the folder from the preferences page here - by default we name it "Unsubscribed mailing lists".
To delete the emails you can log into your mail provider, locate the folder, and delete all the emails in there!
If you have already unsubscribed without this setting enabled then can still I'm afraid we can't move these emails, but we are working on a way to do this in the future!