Go to the Unsubscribe channel in Slack
Write the email address of the user you want to unsubscribe. Just an email address and nothing else.
You will receive a response whether your user has been successfully unsubscribed.
If a user is not found, they may not be in our lists or have been unsubscribed before. In Klaviyo, even if the user is not in our lists, the contact will still be added to the Suppression list (Unsubscribed)
If you do not receive a response from both Klaviyo and Expert Sender systems, please let Mykola Bondarenko know.