On the off-chance that someone in Microsoft customer service might read this:

After my speakers failed, apparently because of a new audio driver, I booked a service call from Microsoft for 5:45 Sunday evening. The call came promptly and a recorded message instructed me to press 1 to accept the call. I did so, long and hard, but the system couldn't hear the key tone. I got two call-backs, and the same thing happened. After the last one, the recorded voice said (approximately) "If you still want an answer, call ..." and cut off.

I then dialled the Microsoft help service number 0800 800 004. After three-quarters of an hour listening to "Thank you for waiting. We will be with you shortly" I hung up.