I've set up a mailing list, but one specific email address / user keeps subscribing to this specific list, over and over and over again. It's been going on for 7 months now.
How can I blacklist them or somehow remove them from being able to sign up again?
They don't respond to email contacts either. At first I thought it was a bug with MailChimp / Slack (I use Slack for notifications) but now I'm frankly just tired of the whole thing, I don't want to see a "fake subscription" from a person who has already subscribed.