iphone 4s brand new was replacment phone ?

iphone 4s brand new only opened to check sim in it guy done this in apple store evry thing in box brand new never used call me on 07762885077 can been seen working theres brand new 02 pay and go sim with it not sure if it takes any sim as guy only tryed 02 sim in it ive the same phone thats why sellin full years werenty we it started last week cause guy in shop acvited it 400ovno 07762885077