On the screen of the phone says not registered and wont allow me to make phone calls or recieve

Please try the following procedure to register the handset:

1. Place the unregistered handset in the telephone base. If PRESS FIND HS 4 SEC ON BASE does not appear on the handset screen after a few seconds, remove the handset and place it in the telephone base again.
   
2. On the telephone base, press and hold FIND HANDSET for about four seconds (until the red IN USE light on the telephone base turns on) and then release the button. The handset shows PLEASE WAIT... and it takes up to 60 seconds to complete the registration. The handset shows HANDSET X REGISTERED (X represents the handset number assigned) and you hear a beep when the registration completes.