I cant say with any certainty what is going on, and can only say what I have seen other accounts do when it comes to agencies. She clearly had access to her accounts on CB and OF, and CB cant be controlled by anyone else, at least not in the US. But CB will act much faster than OF because they have direct help with these kinds of things. Its one of their stronger user protections on both ends.
This is only hypothetical here because there isnt a direct way to know anything right now, but whatever amount of content they have, not everyone subbed has received it yet. Also, not everyone is on this page or other places, so they may not even know anything else. If she was able to contact OF about her account, and wants to shut it down, she will have to submit certain documents and also withdraw her payment methods. This puts the account in a type of lockdown on that side, so the agency cant send anything, but they would still have limited access until this is resolved. She would be the only one who could technically do anything. It also comes down to if she entered into a contract with the agency, which she likely did. The terms of that contract are unknown here, but this isnt a reputable agency anyway, meaning they do some dirty shit to people. They could also be submitting the contract showing what she agreed to, and it will have to go through a review process and be ruled on in a way.
Yes, if you go to her page without logging in, the subscribe option is still there. If you are already subbed, you wont see anything different, at least not yet anyway. If she was the only one using her page, no agency, shutting down the page is much simpler. Again, another reason why agencies should not be used and girls should be extra careful if they do. This is where OF can be a total shitshow on the creator side. If she, or anyone for that matter, sign away their rights to their content to an agency, the agency will then have some ability to keep the page open, even if its to milk new subs and a few buyers. It essentially costs them nothing but time and another page under their belt. This is all too new to know more yet, but the only way anyone will know anything is giving it time.