have had a engineer visit, line ok. Have a bt8500 cordless phone, the incoming call does not ring on the phone but does ring on the base hub. As it is a cordless phone, when the phone is in one part of the house and I have a phone call I can't hear the base ringing . I also have a blue oblong box on the display panel with the word FULL and a red cross over the bt logo. also I can't scroll through most of the options on the phone. any help would be appreciated.