Who or what is Brivia Comm LLC? The # is 408-907-9109.?

I'm getting calls from them all the time. Whenever I answer, I get a dial tone,people talking in the background and I'll hang up, or I get a recording saying "Hold please for important message" and I hang up. Who is this? Anybody else getting these calls? If you stopped them, tell me how to stop them. I've started screening all my calls and I'm a bit afraid,. Are they calling to see when I'm at home or not home?Why am I getting these calls?