Called me once (so far), started his sales speech about a security system, told him I was not interested but he kept talking.  I just hung up.  

The caller seems to be in a public place such a bar, it was very noisy.

Leaves messages, hear background noise sounds like voices, nobody talks, every week

Called like more then 4 times. Whenever I pick up the call, no one talk, now whenever I see that number I don't bother picking up.

Called me once (so far), started his sales speech about a security system, told him I was not interested but he kept talking.  I just hung up.  The caller seems to be in a public place such a bar, it was very noisy.