I was a telemarketer for 4 days. I could not stand what they were wanting me to do, lie to people just to make a sale. Some telemarkers really do not like what they do, they only need the money. I felt really sorry for the people I had to call too as some were really nice old people who were really lonely. And my boss was all about sales. Most of them do not really care about people, just about profits!!! I say this from firsthand knowledge!!!
I had Caller ID too, and when I saw unavailable on mine, I let my machine pick it up.