Report "All my Clarity D613 cordless handsets give the "in use" tone when I try to use them. I've unregistered and reregistered all handsets successfully and erased all messages etc. The in use light on the base is not on and the handsets do not say "in use." My telephone service is fine - I called the service people to check the line signal. Still, if I turn on the phone to dial, instead of the dial tone I get the pulsing busy tone"