Is there anything I can do about my therapist blocking my psychiatric services?

I had a dispute with my therapist regarding an appointment cancellation. Now, she is blocking me from seeing other psychologists at the same clinic (which takes my insurance), which is also where I get my psychiatric services. There is a strict 48 hour cancellation policy, and my appointments are at 3:00 on Tuesday. I called to cancel at 4:30 the previous Friday. I was late, so we contacted my doctor to tell her that I would be out of town. She said I could do a phone in session. The thing is we do double sessions.