Patient no-showed their SRP appointment for the THIRD time

We blocked 2 hours for this patient's SRP. They no-showed. Rescheduled. No-showed again. Rescheduled again. No-showed today. Each time they have an excuse. "Forgot," "car trouble," "family emergency." I'm done. I'm going to dismiss them from the practice. I can't keep blocking time for someone who doesn't show up. But I feel guilty because they clearly need the treatment. Am I being unreasonable?