I've not tried booking her, but I've had a similarly frustrating experience trying to book other girls from the same group. They're only available at odd times, they never put their availability on their profile, and they're a nightmare to get hold of. Unlike some girls they do reply to their emails, so that's something, but when they do it's always too late or too cryptic to be of much use.
It's frustrating, there's a couple of them I'd love to book, and they seem to be genuine enough, just utterly hopelessly disorganised and unhelpful.