Called,didn't leave a message.
Called me away from the important work I was doing, important to me at least, to handle their rubbish.
As the phone system is computer controlled, it would be easy to write a control programme that checked the calling number and rejected it if it was unallocated, as this one obviously is.
I have written such programmes in other fields.
I wonder why no-one has done so?
What was I doing? Working out a cheap, simple, clean solution to Global Warming...