Not much advice here, but I just want to offer you some support.

I'm really sorry to hear what your previous therapist said. I don't have BPD, but even *I* would be very upset with that.

The only suggestion I have is maybe consider writing a letter to this new T. I did that with my current T to give her some background info on me, and she was able to help me out much more than I thought she would be able to. I even told her what upset me about therapy and what doubts I had.