Oh, no! Did you send her an MFC Mail (You can still MFC Mail her as long as you're not put on ignore)? If she did ban you on her own, and is pretending she didn't, that's shitty. But that might not be the case here. These popular cam sites get pretty wacky at times.
I'm only asking because, a few years ago, a favorite MFC reg of mine told me that MFC had briefly banned him from my room...and then just like that he was able to get back in. And then I remember a time when a few models said they had noticed spies during their true private shows (That's not supposed to happen in true private). And just last night, I was watching a guy's cam while in public chat, and he was unable to respond to my private messages. Yes, this was after I had added him to my friends list and enabled PM's for 'friends only'. It was pissing me off, because it was a rare occasion where I actually wanted to have a PM conversation with a member, but couldn't. The little moving pencil icon was up too...showing me that he's in the middle of a composing a PM message back to me, but they weren't sending, and he said it kept saying "This model is not accepting private messages" on his end.