Using computers, high speed internet, & voip. If your phone number is between (000) 000-0000 and (999) 999-9999 you will at some time be called. Foreign criminals pick an area code, & dial every number. With computers', they can make millions of calls a day. At some point they will get you. The do not call list is excellent when dealing with honest companies. With scams, you are not.
They call about one a week for the same scam...."free" cruise..except for "port fee's" after wasting their time for a few minutes I ask how is it "free" when I would have to fly from CA for FL...silence.
I get a call from this number every week to week and a half. I answered the first time and there was silence on the other end. Now I don't answer at all.