Mine FORGOT to call me back when I left a message (on private vm) crying so hard he could barely understand me (as described later)...he was a bit embarassed and said it was one of those things that just "slipped through the cracks". Huh. So I know I can't count on him to return jack**** BUT now he has email and his attention span seems to be better if he can see the words I write.
My point being (besides that I am not "pro-T" today), some T's get "busy" or "forget" and actually don't return important calls... it's rude, thoughtless, or could even turn out to be dangerous.
Anyway, hugs to you and I am sorry this happened. I would definitely inquire when you see her/him next about it, and if you don't get a clear answer, ask how if you need an extra session in the future, how to go about getting one.