a wild girl keep saying f***ing me wtf

I don't know who these f***ers are but they keep calling during the day.  They never leave messages so I don't even know who they are looking for.  I work nights so I am asleep when they call.  When you call back the displayed number, you get a voice mail.  

Anyone have a dress on these guys?  I would like to make a personal visit.

Angry fellow keeps ringing and ringing...ties up my business line and my cell line.  Costs me greatly in opportunity costs, as my phones are my tools of business.  I have to wait until it stops ringing, and often he calls when I am on a call, so I have to listen to this while trying to do business.  Seems to be a debt collector, but he is so rude (based on the one time I actually conversed with him), and despicable in behaviour that I cannot imagine he is any good at his job.

I'll see if I can block the number.

I got a phone call from this (416) 935-2840) number today. She asked me one of my coworker. I said that he no longer work for us, but still she calls me every day and asking for the same person. I think these people are from collection agency.

Rude is only the half of it -- he tried to get me to give him bank account information so that he could set up payment plans with American Express for me.  When I said no thank you the rudeness really started.  I called AmEx and they have no idea what is going on.