I'd suggest starting with the case manager. The therapist has already shown that she's unwilling to listen to you. In any relationship, therapy or not, that's a death knell.

Brainstorm a bit, make a list of what you want to work on in therapy. We've found being assertive with medical types has often gotten us the help we need in a timely manner. My list would include things like improving internal communication and help with ptsd and trauma issues.