A few days ago I discovered about 3/4 of my contacts were missing from my phone contact list. Online chat with 2 different techs (including giving one remote troubleshooting), neither of which could solve anything.
How and why did contacts vanish? No idea (I certainly didn't delete them).
Were they backed up? Certainly, but surprise! Only the ones still present on the phone could be found.
Have I got all my contacts on Google? You bet.
Have I got them on Microsoft? You bet (except the Microsoft exchange isn't working, don't ask me why).
Have I got them in a csv file on my laptop and in my phone files? You bet.
Can the techies tell me how to get them back in my phone contact list? Not.