I've made an app specifically for psychologists and therapists. It helps track your records of missed appointments and helps you follow up and get in touch with that person. Coming out with it in a few days and looking for a qualified person to test it out for free and keep it for free. An honest review is the price. Let me know, please if you're interested.
The app runs locally on your device and there is no information sharing or collection beyond the app retaining your password and email for your security. No info selling either.