I've had nothing but good experiences with her, so i'd be curious as to your explanation as well. She's super nice and tries to give everyone as much attention as she can, even when they're not tipping her, as long as you're well-behaved in her room she'll treat you right.
That has been my experience.
The only time i've ever seen her not deliver was when the guy got upset 30 seconds after tipping because she wasn't naked yet and he started insulting her, that is understandable to me.