No anti-virus in the world will catch everything that's why we recommend people carry at least one extra anti-malware application to be there in such circumstances, such as Malwarebytes free or similar.
The free tools you speak of work differently from anti-virus applications and are meant only as a supplemental protection not a replacement.
These types of malware are difficult to deal with in that they are fake and spoof genuine software and only get hold of your machine when you click on any link or button they display.
Keep your machine totally up to date and protected and be ultra careful what you click on and/or download.
Moved to a more appropriate area for this discussion.