Got replacement 4s

Had trouble with 4s re caller ID it would not turn on or off.... Funny the same thing with my old 4 have been unlucky with apple this is my 5th replacement due to hardware software issues..... Anyway my question apple in Boston told me to set it up as new phone where as my mobile provider here in Ireland said to restore it from backup........... What's the best thing to do.... Received a brand new one from the store... Thanks