.... Last Saturday morning I received a
"Microsoft Security" telephone call from an English-speaking Indian about a virus on my computer ...

I used to think that I was the only one so privileged as to get this kind of crap.
For variation on a theme, we've received persistent phone calls over the past several years - sub continental accent - from the "Australian Government" asking if we have solar panels on our roof. I've no idea what this is leading to because I am so peed off with this that I now hang up after they are unable to tell me which department of the 'Australian Government' they represent.
One of them rang me back 4 times last Saturday morning!
One day when I am in the mood, I simply must let this travel to a more educated conclusion.
They really must think we are totally ignorant, stupid or worse.
Our phone numbers are also on the
Australian Do Not Call register, but that seems to make no real difference.