Hi @impactpixel, thanks for reaching out!
On site alerts, there is a link at the bottom of the email stating No longer an administrator for this site? Click here to stop receiving security alerts that should have the desired effect.
This has been put in place for a scenario where current site administrators aren’t responding, or can’t respond, to requests for your email address to be removed from the site. If the version of Wordfence is particularly out of date or you are unable to find this link in your email, the best course of action is setting a rule to direct these emails to another folder so that they don’t appear in your inbox.
If it’s a site you used to run but it’s now inactive, hosting for the site’s WordPress folder is still active somewhere and executing PHP. If that’s the case and you no longer have access to the account or server, I recommend contacting your previous hosts to tell them that you would like all data removed.
Many thanks,
Peter.