[AC Question]

I have lost all my contacts & don't know how to recover them

[anon8380037]

Have you opened the Contacts app and checked the Contacts to Display options from the 3-dot menu.
If they're not there, and you think they are all Google Contacts, you can check in Accounts - Google that Contacts is checked.
Same if they are Samsung contacts on the Samsung account.
Device only contacts can be synced with pc software or will be lost if deleted.

Let us know what device you have by registering and replying here if you need further help.