oh googley (((((hugs)))))
I can relate to this SO much. SO SO SO much. It has taken me a year of working on this exact issue with my T to get to where we are now, and it caused me a lot of tears and pain along the way. She would tell me to call her, but then not call me back, or call me but only have 5 minutes to talk, things like that. She would tell me she'd call at a certain time, and then not do it, and when I asked her why she would say she forgot. That still happens sometimes, actually.
But anyway, what I want to say is, keep working on it with your T. Keep talking to her about this exact thing, week after week if you have to. I have talked about it with my T SO many times. We came to the conclusion once that things were just ****ed up with us as far as the phone thing goes, and that we had to try harder. SHE had to try harder. And she really has, and it's gotten better, and now I know I can call her and she will probably be there, but even now sometimes she's not and it still hurts.
So yeah, I know how you feel, and how alone that feeling is, and I'm sorry.