When I answer the phone no one responds. I have called them back and when someone answers and I voice my complaint they either do not respond or they hang up. I want them to stop calling period.

This company (scam) calls at least three times a day. Several times, they have hung up just as I answer. I have call waiting on my phone and when they call, and I'm on the phone with a business client, I miss words while it is beeping. I have asked them politely each time to take this number off of their calling list and they respond that they will. Then, the next day, I get three or four more calls. I have started asking for their number so that I can call them and disturb them all day long. They usually hang up then but one did give me a number that turned out to be bogus.
What can I do to get them to stop calling?