[MarcelDuhamp]

Nomorobo - (iOS)
This is my best of these apps I’ve reviewed to date — so it’s no surprise that it won a competition by the FTC. After you download the app onto your device, you can sign up for a free trial for 30-days, or commit right away to either $1.99 per month or $19.99 per year. (If you don’t remember to cancel your sign-up, you’ll be auto-billed.)
After you install the app, it prompts go into your iPhone’s settings, select “Phone” then tap “Call Blocking & Identification” and tap Nomorobo to enable it. Back in the Nomorobo app, it asks you to enter your phone number for verification (to make sure you’re not a robocaller yourself). After that — you’re done.
You can send yourself a test robocall to see exactly how it all works. When a sketchy telemarketer hits up your phone number, your call screen shows a big red dot and a note that says “Robocaller” so you know to avoid it. There’s even an option in the app to block these calls automatically, before they even reach your smartphone screen.
Nomorobo swears it doesn’t block legitimate calls from pharmacies, schools, or other important institutions — because it “analyzes millions of calls made to hundreds of thousands of phone lines every single day.” While it doesn’t want to say much more about its secret sauce than that, I’m using it and it seems to be working well.