I'd try and speak to your T about it. It's obviously something that is bothering you and hindering the therapeutic alliance, so it's worth bringing up. Depending on the response you get that could help you decide whether this T is the right fit for you or not.

One thing to consider is that her receptionist might not be passing messages on, or at least not doing a very good job of it. I've called my Pdoc to arrange rescheduled appointments and scripts and at least 3 times he never called back because the reception staff forget to even bother to check whether he was at work and he was actually on a week's leave.