Demi Lovato explains everything on her twitter account:
There are so many crazy rumors flying around today. I'd like to clear a few things up. First, Joe and I did split but it wasn't over the phone. Things didn't work out but we'll remain friends. Secondly, I am NOT dating anybody already. Nothing is more important to me than the relationship I have with my fans.. Just thought you guys should know this.So there it is, everything's cleared up. Demi and Joe are done and Demi's not dating anybody.