I arrange all my appointments through my therapist's secretary, so I don't have to deal with my tdoc not setting up my appointments. That's a plus, but I know not every therapist has a secretary.

You have to remember, you therapist has a whole other life outside of you. I don't mean that to sound harsh, but sometimes we forget that and take things personally when they aren't at all meant to be personal. Text her and simply say, "Call me so we can set up an appointment." I know you think she doesn't care, but that just isn't based in reality. She'll get back to you as soon as she can sit still for a minute.