I am sorry that you feel so upset and this happened to you. I understand your reaction. You felt hurt by your therapist's reaction to your expectation that she would give you the time you deserved.
I think it is good that you told your therapist how you felt. That is a good response to what happened.
Most people would be very upset about being shortchanged by their therapist. You expect your time and when the therapist was late, it was her responsibility to make sure you got the time you paid for. When she did not give you your time, she violated the trust you had in her that she would take care of you and be fair to you.
Let's take a look at this from another perspective. When you think about what happened with your therapist and think about how you felt, does it remind you of another time you felt this way? Maybe in your childhood?
When you felt these feelings and decided to act out your hurt, what thoughts went through your mind?
I am asking these questions to clarify the possible origins of your feelings and also to get a better idea of your thought process when you act out your feelings. This will help us figure out better ways for you to express your feelings.