I almost never get unwanted phone calls, if someone rings me on the mobile and I don't recognise the number I don't answer it, simple, if they leave a voicemail, they' obviously want me for something in which case I might ring them back when I have 2 minutes free
I also don't advertise my landline or mobile numbers as a rule, to ensure I don't get unwarranted calls.
Unfortunately in the US these days there are any number of databases that advertise one's phone number even when it's deliberately unlisted, apart from all kinds of personal information most people would just assume keep to themselves. I could change my number again, but sooner or later they catch up with whatever is current.
Creepy what you can get even for free these days online:
https://www.mylife.com/
In my own case it's easy not to answer any number I don't recognize. My vendors never contact me by phone, leaving only my cousin or brother. Everyone else, 99% chance they're either criminal scammers or telemarketers. The big scam right now are criminals using the "neighborhood scam". Where they use they spoof numbers using the first six numbers of your own phone number to make it look like a friendly, local call. Of course I don't fall for that either. One thing for sure, no one is abiding by the federal no-call list. Signing up means nothing now.
The only ones who ever leave messages are the IRS impersonators...who don't fool me at all. Kind of funny to listen to their pitch though. Problem is, the IRS notifies you by certified mail if there's any kind of problem with an income tax return. They never cold call anyone. And the US Treasury Dept. doesn't send county sheriffs to physically arrest anyone...lol.
I still use nomorobo.com to filter out the obvious scammers, but these days they are using mostly the neighborhood scam which spoofs legitimate numbers of real people. And they cycle them through so they seldom use the same number. But I just let them ring twice and hang up. Either way they never get to me.
The rest, I simply block if they use the same number more than twice. I make it my business to waste their time, resources and livelihood more than they waste mine.