I'm wondering if maybe the other person was a new client and maybe it was her first appt. with T. It would much harder to forgive a mistake like this if the person doesnt even know him yet.

Or, maybe he decided not to see you after you went back and talked to him. Did you say anything to him that might have made him choose the other person? I'm wondering if you stormed back and demanded to be seen while the other person sat quietly in the waiting room.

I would be pretty livid too, especially since it's your normal time slot!