I think I got on their blacklist!
I was trying to beat my mate Dave's record of 45 minutes... Unfortunately something came up so I had to cut it short. After thanking them for their time and entertainment, where they still remained in character and continued with the "but you really need to fix your computer" line, I announced I was an IT professional (both hardware and software) and would happily run rings round them another time if they'd like to arrange a convenient date and time.
This finally made them break character, and I think I learnt some new words in Urdu.
I replied with a nice selection of Anglo-Saxon, French, German, Polish and Hungarian curses.
(Yes, I'm still a 14 year old who can only remember rude words in foreign languages!).
They've never called back.