Delete or unsubscribe a contact
We don't recommend deleting contacts but changing their status to unsubscribed. This way, you can't accidentally re-subscribe them later. Unsubscribed contacts are maintained in your list, but no longer count towards the subscriber limit of your plan.
For each list where the email address is Subscribed, do the following:
Click on the list. Below the list menu, you can find a search field - click the magnifying glass to search for the email address or find it in the contact list and click on the address.
All unsubscribed contacts are at a list level, as opposed to a global account level, so you must repeat this process for each list you wish to unsubscribe/delete this contact from.