Thanks, Rigo.
To the best of my knowledge I did not remove any contacts or contact accounts when upgrading the iOS to 16.0. It appears that any such removal occurred during the upgrade process without my knowledge or intervention.
This is not an issue I have dealt with during my many years of iPhone use so I appreciate your advice.
I looked at the contacts account lists for something I may have had that I could remember as now being missing and the closest I could come is an Outlook account so I added it back to the active list and rebooted my phone and it may have solved this problem, although I can't yet sign an affidavit because I have many contacts and do not remember what all they are.
I shall keep my fingers crossed.
On a similar issue I have heard from friends who have lost their iTunes libraries during upgrades and I am worried about that happening to me.
Thanks again,
--Bob