some one called to collect a debt from me, but I do not owe anybody anything

I received a computer generated call today from this number asking for Rosco Cook.  Instructions:
Press one (1) if you are not Rosco Cook; press two (2) if you need more time to get Rosco Cook; Press three(3) if this is a wrong number.  After pressing three a man came on asking "Is this Rosco Cook?" to which I replied "No, you have the wrong number."  He said "Sorry." and we both hung up the phones.

I felt uneasy about the call and wondered if it were a scam to have access to your open line and some how make use of it.

I just got a call from that number and they hung up on the machine, but I get recorded calls like that a lot bc I owe some hospital bills.  They are a pain in the butt.  I think if they are a legitimate collection agency they should not call you back if you say it's a wrong number.

The strange thing is the other place that calls, I don't know the number off hand, but they leave the automated message on the answering machine, so I always wondered how that worked bc if you can't push any of the buttons to respond and just about the whole automated thing gets recorded.  I don't answer the phone if I don't recognize the number.