I get them all the time. I usually don't answer and wait to see if they leave a message. If not I just don't bother with it.
When you answer and nobody is there, it is just a computer. By answering you are telling the computer that your number is a good one for a live person to try later.
It's funny that this thread popped up when it did. This afternoon, I received three random calls. Two came up as unknown and the last one had the number 0000121233.
When I started my current job, I was given the choice of getting a company phone or just having them pay a reduced version of my service plan. I wanted to keep an unlimited data plan and have had a separate work cell at all of my previous jobs, so that's what I asked for. Well, every month on the first and the fifteenth I was getting text and voice solicitations on this work cell for payday loans and calls about "personal financial matters" for "Tristan." At a certain point I started pre-emptively asking them who they were calling for, some of the more aggressive callers would claim they were calling for "you," but I'd still ask them to put me on their no-call list. So, you may have an old or recycled number.
