I completely understand your frustration and upset at your therapist missing your appointment, but I think that it's a mistake to jump immediately to notifying the board of her wrongdoings/mistake. Think about the possible repercussions on you too, sounds like you're working with an agency that has multiple therapists under one general managing. If it was processed that this complaint had little merit to it, you could be seen as a difficult patient making other therapists reluctant to work with you. But I also understand you're going to do what you think is best for the situation, I just hope you sleep on it.