The problem is these companies often have people all over the US calling your phone to try to scam you with health insurance or other offers.  I just received a call from this number, didn't answer, and now am receiving numerous calls (usually 5 or 6 back-to-back) from different numbers for the same company.  Most of the time if you ask them to take you off their call list, they will hang up on you or are just downright rude.  I've heard of people getting up to 30 calls from different numbers each day....for weeks.

I have the app, Call Control, which helps.  You gain access to their database of scam numbers submitted by others with the app and it will block reported numbers from calling you.  The basic version is free.