stopped in my tracks with this page

[gryphon.john]

I have the premium Avast paid for program and today this took over my computer,(attachment) the cursor was unresponsive and I wasn't going to phone the number. Received advice to do a hard shutdown from a learned one and that solved it.
Is this a new crapola or is it an old one? I have no idea as computers are not my language.
I wonder how it got through my Avast defence?
Thank you Gurus.

[Pondus]

I wonder how it got through my Avast defence?

Because it is not malicious, just a fake message
The malicious part come if you phone that number

[gryphon.john]

Ok,it was malicious enough for me because my mouse cursor would not respond to any moves at all and I ended up doing a complete shutdown to get rid of it.

[Cluster-Lizard2014]

Even if you did not respond to the message I'd do a full system scan with AVAST after anything like this and probably run another anti-malware sweep using Malwarebytes just to make sure nothing has been sneaked onto your PC.