Okay so right now I own an iPhone 4, I'm a little behind. My 2 year contract hasn't expired yet and I don't think it will matter anyway. I found an iPhone 5c 16 GB unlocked that is used that I plan on buying. To activate that iPhone would all I have to do is deactivate the 4 and then pay a small fee to activate the 5c for use? Or is it not just that simple?