Help! For some time now we've had an intermittent dialling tone as though there is a message waiting to be picked up. Have tried to resolve this through ringing home phone to leave a message but the answer system doesn't pick up (can't remember if we've activated it or not as we have a separate answer machine we normally use!). Have also tried 150 with no result - ended up being cut off for some reason after half an hour and 3 different departments. Don't know what else to try but it is beginning to annoy me!