Write him a three or two star review on google maps and Yelp. In the first paragraph say he is is good at whatever he is good at.

In the second paragraph say However, Dr. xyz takes on more than he can chew as a psychologist, and suddenly bails out of longer term cases that catch him off guard suddenly that he lacks the hard skills . Say while you recommend him for short term or CBT, that he isn’t a reasonable providor for long term psychodynamic therapy.

At least he will hear you, and will be held accountable. The more balanced and reasonable, the more effective. Write line a supervisor, not an upset client.