received a request for money from this number. do not send them money they are frauds and they should go to jail.

I repeatedly get messages from this number referring to a person who does not live here (obviously they have the wrong number).  When I try to contact them and tell them they have a wrong number and to quit leaving messages on my phone they tell me it is their job and hang up on me.  They appear to be a collections company of some type but I do not owe any money and they say the message is for a person that is not me or my family.  How do I get them to stop??