Yes, I just received a call from Isaac Cohen as well. Let the phone ring 3 - 4 times and then it stops, it's a Telemarketer. Why would one want to do business with these people when they obtained your phone number illegally. OPT OUT, means OPT OUT people!!
There has been so many post on this site explaining that the DNC list does NOT do what you seem to think it does, that I don't see any reason to say it all over again if you just refuse to understand it. But, in summary, it is NOT a call blocking service and it only stop legitimate businesses that subscribe to DNC. Scammers don't subscribe because the are criminals and don't care about the law any more than any criminal does.
My phone has already had this number blocked, but this is first time I've seen "Isaac Cohen" on the name. Now I actually feel sorry for the real guy whose name is now stuck with these calls.