Had one the other day. Went t6hrough the waffle and he asked if I could see the webpage I had been asked to navigate to. Told him - "oh do I need an internet connection"
Then told them to wait 10 mins while I connected and was then asked if I was on the web page, told them I had clicked on the link but my PC was telling me it was a nasty piece of software, I told them I had installed it.
They then asked for the 9 digit number which was displayed, so gave him a made up nu,mber at which point I could hear his PC bleep as he tried to connect to my non existent pc !
He pondered and the tried again asking for the number again. He asked what was my PC doing - so told him it had told me someone was attacking bit and I should call the police .....
He hung up