You're overreacting. Besides, an hour each day on the phone isn't very much. Just because she chooses to converse with someone on a regular basis you're going to break up?
Honestly, You're being incredibly immature.
I see nothing wrong with her behavior. Rather, you seem like someone with jealous, overposessive tendencies. So she calls him often. Tell me, why is this not acceptable? Certain things that you don't do in a relationship? Why? So if there are some things that in your eyes you deem unacceptable, they are automatically taboo? Don't be irrational.
At any rate, I would say that talking to her about this issue is important, but the attitude with which you use to address the situation is entirely wrong altogether.