I can see why you'd be annoyed, but a negative seems a little harsh for someone bumping you by 20 minutes, especially considering you hadn't told her what booking you wanted.
Clearly bad comms on her part, but was under the impression the Hungarians in Cardiff were like Soho girls in that it's a case of when they're free, they're free, and in fairness you'd already turned down one time and told her you weren't sure what you wanted, I can see why she'd prioritise and earlier, more concrete booking