Yeah I think it was low ticket sales, Yahoo wrote about it saying that her excuse was basically bull****. You plan a tour months in advanced. You don't announce a tour and then all the sudden say you aren't touring because you didn't manage your time correctly. She and her people would have had to been in contact with them months ahead of time to book the events and dates for the tour. It's more likely, that they looked at the ticket sales and said Christina' this isn't going to work and that led her to cancel. Her ego probably couldn't handle singing to more then half empty arenas.
that's primarily a Maroon 5 song... That doesn't show they're still there for her