Creating a suppression list or blacklist
We don't offer a global suppression or blacklist. Instead, we recommend importing your suppressed contacts into your list as 'unsubscribed':
When importing a contact list there is an option of whether the contacts should have a status of subscribed or unsubscribed. If you have unsubscribed emails to Import, separate the two list files then import them into the same Master list. Import your exclude list with the status unsubscribed.
This will prevent those contacts from being re-subscribed if they are inadvertently imported into your list in the future.
All unsubscribed contacts are at a list level, as opposed to a global account level. As all lists are treated independently if you have multiple lists make sure you import your exclude list each time!