I have this same problem just now let me tell you what happened
I HAVE THE GALAXY STELLER I BROUGHT FROM EBAY THE MAN SAID HE ONLY USED IT FOR 10 DAYS.
ITS A VERIZON PHONE BUT I WAS GOING TO USE IT ON PAGE PLUS NETWORK.
I CALLED THE STORE JUST 5 MINS. AGO TO ASK THEM COULD IT BE USED ON THERE...