Nightsky

Give yourself some grace.
I can relate to many things you wrote in your OP. Trust me, I know "INCREDIBLY complex". Take a deep breath.
During the height of my "incredibly compex" situation, there were multiple T's involved. All of them knew each other on a professional level, a couple were personal friends. It all felt unsafe (and also unfair).
I won't get into the specifics here but I would gently encourage you to see a T who is not referred by your recent one. Consulting the one who T referred is an excellent idea. She will be able to help you find someone who has some distance to the situation. As someone has mentioned, just because she does not accept your insurance does not mean it cannot be filed. In many cases, the T can fill out a superbill and YOU can file it and get reimbursed.
Like you, after therapy ended, I reached out to T. He knew me. We had history, it made sense. T reached back because he cared. He also had regrets (terminating me). It became (EVEN) more painful and hard.
I'm sorry this happened. Whatever you decide, I trust you will know what is best for you.
"...you are braver than you believe, stronger than you seem, and smarter than you think..."-Winnie the Pooh