scum of the earth call all the time

I get calls all the time for a man name Rowland Block but there's never an option to say it's the wrong number.

they call and ask for someone that I don't even know, and I have a cell phone.

I keep getting calls from this number and when I say hello they hang up or they just stay on the line and then hang up.  I have called back and am left on hold for a very long time trying to find out who this is.