I don't know if it is but, just in case.....
Phone rang saying 'International Unavailable'. I usually ignore them but, at that time of day, it can be our son in USA so I picked up. There was a brief silence then a ringing tone as if I'd just dialled out. I cut it off quickly.
This might be a variant on the automated call but I thought I'd warn everyone in case it's a means of getting the person who's receiving the unwanted call to pay for it.
“There is always a well-known solution to every human problem - neat, plausible, and wrong.” H.L. Mencken