Answered the call, I have new Panasonic phone system which allows me to hit a button on the phone unit to block the call. It was "Congratulations, you have won a trip to the Bahamas", by answering I can confirm it is, in fact, spam.
Called me 6 times in a row until I answered, they stayed quiet, no response, I called back and it doesn't even ring. It automatically ends call. Have already added it to my rejection list.