With a manager like that, it's pretty easy to understand why he's not doing that well commercially
On another note, though, the Twitter user is a Harmonizer and she's completely insane. She practically stalks Camila every time she goes back to Miami, and she's sent threatening DMs to other fans who have met Camila telling them that Camila doesn't like them and that they need to back off

I know that's obviously not an excuse for being insulted like that (especially by somebody who's supposed to be "professional"), but I find it hard to sympathize with her.