Here's another trick . . you know the 3 tones you hear when you've called a number not in service or has been disconnected? It's followed by the message ( . . the number you have reached, . . ) Record the tones, and place it before your greeting message on your answering machine or voicemail. Most telemarketers use automated machines to dial phone numbers. If they hear this tone, they automatically disconnect, and many of them take the dialed number off their list.