This number has called me once a day for the last week, and I haven't picked up for any of them. They have never left a message. It seems to me that even when you pick up to say 'hello?', a lot of these call systems recognize it has reached an actual person so it maintains your number in their system (and may share those culled lists with other companies/scammers). If you never answer, it may drop your number from the list and not try again. I never answer numbers I don't recognize, even if they're in my own area code. If you really need to talk to me, you'll leave a message.
The cid showed "unknown name" and phone number 818-643-4913. Robo message from goofy Emily about a vacation. This is one of many calls from Emily and from many different phone numbers.