Yes, the SimplyCast list management system will check the lists you are sending to against the records on your unsubscribe list. If an address is on the unsubscribe list, the system will not send the campaign to that recipient.
This would put our customers in a murky gray area with the law, if a customer opts out, they are rescinding their consent to receive mailings. In order to avoid the potential pitfalls of this for us and our customers, we opted to not allow individual unsubscribes. This should be made clear to the customer on the unsubscribe page so as to avoid miscommunication.
Our support staff will have to fix that for you. Get in touch with us by using the information provided on our contact page.