keeps on calling with no message left

I am never home when this number calls but sometimes this number calls more than once a day.  When I try to return the call I get a recording about dialing the extension of the person I am looking for.Who is this that is calling and how do we report it and have it stopped!

have received phone calls from this number the past 3 days.  Today When I received the call, I answered put my phone on mute and waited for someone to begin speaking... waited at least 15 seconds before a woman began asking for someone under my name- since I did not respond she stayed on the line for another 30 seconds saying hello hello are you there hello, etc. (lol)she then proceeded to hang up- she did not state any information related to the call.