Updating my new number on my 4S

Hi everyone! I'm new to the apple community so I'm not sure if this is the right place to post on this thread. So I just changed my mobile number with 3 and the adviser told me to turn off iMessenger so my new number would display on contacts but my old number still shows and it still shows on the 'Phone' settings. But my new number does show on iMessenger and FaceTime. Can anyone help me?