hello I have had an easy fit telephone alarm system fitted for a year now. This week I added a new device....a keypad. Now when I come home and disarm it, the external siren sounds. Internally the alarm doesn't go off and there is no indication on the screen display to note that the alarm has been triggered. Wondering if I haven't paired it correctly and should forget the device then re-pair it. Any help gratefully received so the neighbours don't lynch me.