The FeedbackExpress Blacklist allows you to stop FeedbackExpress from ever emailing particular customers. You can reach the Blacklist under the 'Settings' menu in the top right of your account. Most customers who populate your Blacklist will be automatically added when they have clicked the 'unsubscribe' link on one of your emails, or if they have left you negative feedback in the past.
Our Youtube channel provides a video guide.
You can, however, manually add customers to the Blacklist if you need to. For example, a customer you know has had a bad experience or has been argumentative via support emails with your team.
Please note: you can control if customers who leave negative feedbacks are automatically added to your blacklist on your Preferences Settings.