You can try Truecaller (www.truecaller.com). This is one of the essential problems we are addressing and it works quite well for +200 million users worldwide..
I got tired of that and replaced it with Mr. Number, which seems to keep itself updated and allows me to ratchet up the blocking all the way to "everyone not on my contact list." That's not ideal, because I might miss calls from my credit card company, bank, etc, but the 2-3 scam calls I was getting every day were driving me crazy.