Sending spam emails to user accounts which you cannot subscribe to.
Received this email "Your contacts are waiting—time to check in with a new email", it's just spam to get you to log in and use MailChimp after 30 days of inactivity. At the bottom of the email it says "This message was sent to inform you of a critical matter. Please note that if you have chosen not to receive marketing messages from Mailchimp, your choice applies only to promotional materials. You will continue to receive critical notifications that are legally required or could affect your service."
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