I answer these now or call them back because I can block with confidence when I find out who they are.
With this one, got a second of someone being there, and then got a fast busy signal. When I tried to call back by redial, nothing happened and the dial tone just continued as if I had not dialed a number. Did this 2 or 3 times to make sure I didn't miss something. Next telltale sign that it is a scam: I dialed the number by hand and the recording that comes on - this phone number is not in service.
Now it is blocked. Don't bother to answer.
I was incorrect about blocking this strange number - when it comes up on the phone's callers list there is no option to do anything with it but erase - which does not help when I want to block it!!
Wow! This never happened before on my phone and the other 2 numbers that came in right before it I was able to block, so it's not as if my phone is our of blocking space. I can't even save it to my contacts so that I can call it "SCAM".