I just bought a Sidekick II form a friend. He told me all I have to do is get a new SIM card. Then the bastard tells me that he hadn't paid his bill in 4 months and they turned off his services, but that shouldn't be an issue if I get my own SIM card. Is this true?? I have no clue because I have benn using Sprint for 5 years? Any help is appreciated!

Thanks
Simeon