I am having some serious issues with my phone! Last week all my contacts disappeared and when i went to restore them, i had no back up, in either samsung cloud or google! But i back my phone up every week as a precaution. And now My Notification panel has today decided to hide itself! I dont know how or why, but i have been through every setting and nothing i do changes it! How do i get it back to always showing!?!?!?!
I know it's not helping solving your issue but do you have any old phones left lying around to smart switch all, most or at least some contacts over? It looks like your contacts were never syncing to your Gmail. Do you use a Microsoft email account at all? You might have them synced to a Microsoft account. Also check your sim memory for any contacts?
I have now fixed the notification panel issue. It was in my home screen settings under slide down notification panel, it needed to be turned off (even though i had not turned it on!)