I have reached the point where I don't try to play games with them any more or explain I am not stupid enough to believe their story.
The popular one is the 'I am from Microsoft and your PC is sending viruses onto the Internet ...... yada....yada'
When you ask them to tell you what the IP address of the PC is they are stumped and get very shirty.
I now just put the phone down on them, saves time and wasted anger.
They don't care if you know it is a scam as there are plenty of victims waiting to be caught out.
They don't like their time being wasted but it is not so easy to string them along like a good old 411 scam.
I think someone who I have given my email to has had their data harvested.
(I rarely give out my real address but sometimes have to and think I have been added to a scam list and worse)
I am getting some dodgy e-mails + scams, they arrive in bursts then you get calm for a few days or a week or so.
That is the problem today, you can be as careful as you like but someone else can have no idea about security and you suffer the consequences.