These jokers can spoof your caller ID. They can make it display any number, functional or not. If they wanted to they could send 123-456-7890.
If you don't know the number. Let voicemail catch it. You can always call back if the call is/was legit..
got the call this morning, did *67 and called it back. machine said "reward redemption" and they had gotten my number from a web site I had visited. The last one said I had signed up for a trip and they got my number from there.