If your user name appeared to be a real first and last name (fictitious or not), your user name has been changed to just your first name. As of May 1, 2018 no full real names are allowed as user names.
I too have caller ID if they don't leave a message I google the number you would be surprised what you can find out.
If what I find out is nothing I want then number is added to my call blocker.
Sometimes if I'm bored I'll pick the phone up but they usually end up wishing I hadn't
If I'm in a bad mood, they get called every name in the book.
If I'm in a good mood, I'll sometimes play along with whatever they are selling/pandering.
Twice I've had my wife laughing hysterically and in tears from laughter. Once with one of those 'Windows security' calls where I spoke broken english and with an accent for nearly 30 minutes with whoever was on the other end. And again with a window salesman when I was constantly telling him we didn't have any windows and I had bricked them all up.
The windows help line is the easiest to mess about with.
I either stop them after a short while and ask at what point did my PC give out my name and phone number or could they call back tomorrow so I can go out and buy a PC.