The important thing to remember is that if you did not call them do not pass control off you computer to them, they could delete items from your computer when you tell them your not paying them, or install programs with out your consent to give them access when ever the machine is on.

The best way to subvert these phone calls it seems is to get a phone that shows the numbers calling you and if you don’t know the number and your not expecting a call let the answer machine get it , or if you don’t have one of these phones just say you don’t have a computer or say thank you i will call my computer man and hang up, Never give them control.