Sixth form problem

Hello, I have a problem and I need some guidance.
I applied to a couple sixth forms, my secondary's sixth form (A) and this other one (B) and I really wanted to go to another one (C).
My problem is that I applied to go to A and B, but I forgot to put down C as a second option as B and C are linked schools (I know really silly of me). So I emailed C a couple days ago (after results day) and they said 'we have put you down on file', even though I didn't do the form. So I called C today and they said there aren't anymore spaces, which is my fault I should have put down C's name on the form. Because B was demanding to enrol asap, and I wasn't getting responses from C, I turned down B's offer. I called B and they said they'll put me on the waiting list. So now I don't know what to do, I'm still enrolled at A but it is far.

Where did you have to put down C as a second option?
Which sixth form do you want to go now?

The schools B and C are linked through the council at the county I live at, A is in another county (I went for a secondary there as the secondary's in my county aren't that good). And I most definitely want to go to C

I guess the only thing you can do is go to A next week and hope that a place opens up at B or C? Or you could try and contact B or C again I guess and see if they could make an exception for you? In my experience though, unless you’re changing schools to a sixth form college where everyone is new, staying at your current school (if it’s a good school) is sometimes the best option - your teachers already know you and you probably have friends from secondary. Anyway, good luck whatever you do - I’m sure it will turn out ok in the end 😊