This is a marketing call with the caller saying, "Hello, hello ... hello ..." as if a friend trying to reach you.  This caller never gives up and never leaves a message.   That seals his fate because unless we recognize the caller's voice as that of someone we know, we don't pick up the phone.   Let your caller ID save you the time not to have to deal with these
unwanted callers.  In effect, they are using your phone for their convenience to bother you.   They have a partner, the phone company, will can stop most of these calls but won't because in setting these people up in business, the phone company is abetting them for their profit motives no matter how much it disturbs your day to have to go to the phone and read the caller ID and realize this call shouldn't be picked up.  I wish I could call the people who are responsible for this all times of the day until they are as sick and tired to their molesting us.