I'm so sorry this has happened!!

I do think T1 should be allowed nowhere near any therapist of yours in the future. She seems like an unhealthy person and the fact that she knew about this before you did is a big red flag. It raises too many questions about what role she is playing in this whole thing. She was not upfront or healthy in her interactions with you- I think it's probably safe to assume she is not upfront or healthy in her interactions with T3.

I'm really sorry you are going through this! And particularly when you were doing so well with T3.

You mentioned T2- do you think it might be helpful for you to touch base with that therapist? Though I would make clear that T2 is not to be talking to either T1 or T3.

The fact that T3 immediately rang T1 to say what happened would be disturbing to me as well. This is not a setup that is likely to serve you well at all.