How to enable email preference management for MemberStack email campaigns?

We were using Mailchimp for email campaigns but the connection via Make was always a pain and cost money and we don't do a huge amount of emailing anyway. Saw that Memberstack had added email campaign functionality – perfect! 

However, as I see it, there's no way to manage unsubscribes. Fine, they're suppressed so once they hit unsubscribe they don't get any more emails. But what if they did that by mistake or change their mind? Is this process really irreversible? We've got email preferences in our user dashboard and would really love to keep using it! 

Any help welcome!