I used Nomorobo for 6 months and it was NOT useful, i have a phone number from a area code + prefix that i dont live at, yet I get about 5-10calls/day from similar looking numbers. Nomorobo would mark them as ‘unblockable’ because of the areacode+prefix match, so i would have to manually block each one.

I switched to ATT Call Protect which works much better. Now i get 1-2 calls/week. I would go back to nomorobo if it worked better.