Sorry for the delay in replying. I ignored Skype for a couple of weeks. When I tried Skype again it worked. It took another week before one of my contacts was available. We were able to talk with no problem. I wonder why I and others received the “not available” message and seemed to be cut off?
Then late in December I was blocked again. This time every attempt to launch Skype was met with a message that it had just signed me out as I needed to “upgrade” to a later version. An online search found some instructions to give the impression that Skype had been changed to a later version just by changing a couple of numbers. ie it is the same as before but with two minor changes. It has since worked fine.
There does seem to be some sort of attitude problem at Microsoft/Skype that causes them to needlessly antagonise users.
Anyway, Skype is working for now - until the next obstruction.