If this was your friends personal phone, have them call in, cancel service, and PAY THE BILL. You can not activate it as your own until then.
If this 'friend' gave you a stolen phone, return that bad boy as all that can come from that is trouble for you. If stolen, once shut off you will never be able to activate it.
This sounds like a stolen phone, or one that is currently on your friend's line.
I agree with Budone.
However, a phone will automatically deactivate when the owner activates a different phone on their line. Thus why it sounds like a stolen/currently used phone.