Try dialing 175 (ON YOUR LANDLINE HANDSET),this should give you your telephone number.Its possible that for some reason,you have a different number to the one you should have!DOH.This would mean the phone rings when somebody dials your correct number(but doesnt ring in your house) but you still have a dial tone when you pick up either of your handsets.Or providing you dont have a "withheld" landlind,you could just dial your mobile off it and see what number comes up.