From what I remember of your last thread about this incident, everyone agreed she was in the wrong to miss your appointment, but many disagreed with your interpretation of her e-mail. Did you never address this issue face-to-face? While you're always free to make a decision to quit a T at any time, I'm not sure it's beneficial to do so and then continue to seek justification through misunderstanding.

Meaningful apologies happen within relationship, and can lead to increased closeness, but only if both parties are willing to invest in them. Ts who won't miss an opportunity to heal; clients who won't miss out, also.