Oh Comrade, a year ago today I could have written your last post word for word, and know only too well the immense pain and confusion that it causes. I am so desperately sorry that you are going through this, and I am not sure that I have many words of consolation. We too were supposed to have six months and then, poof, just gone. No gravestone to visit. No closure. 4 months after the event I did have a termination session, and it helped. Massively. At the time I hated it because I didn't feel like I had enough time to go through everything that needed saying, but having her sit there and listen as I vented my anger and my hurt and my pain did help. Only because she accepted it, and apologised. And that isn't guaranteed, sadly.
Personally, I would push for it though. If not you asking, maybe this new therapist. Can they contact her and ask WFT professional to 'professional'? (in MASSIVE inverted commas because how she has gone about this is far from professional). I think most decent therapists know the importance of an ending, even if an ending is NOT what is wanted.

I know I am also lucky in other ways, as after that termination session we have stayed in some form of contact. Just the odd one line message every two weeks or so but God has it helped me to get to the place I am now. I still have days where I miss her like nothing I have ever known before, but there are also better days, where I can see a future and I can see the sunlight.

I get the sense that you had a turbulent relationship with your Ex T, I don't think many people with attachment and trauma wounds would say that they didn't, but it must make it really difficult for you, and again, I am so sorry that you are in that position, not having had any time to work any of this through with her. Not knowing. Not understanding. All the feelings and no idea what to do with any of them. I don't really know what to say, other than I really hope that you can find a way through this to a better place. Take care of yourself...