Turning on contacts toggle does nothing

Unlike some Android devices, contacts are neither stored locally on an iPhone nor in SIM. They are synced to an email account that you had Google, iCloud, AOL, Exchange, Outlook, Yahoo or any Other

If Contacts on iCloud, try this --> Restore contacts, calendars, bookmarks, and more using ...

Else add the email account that stores your contacts.

You may get faster responses to your query by --> Writing an effective Apple Support Commun… - Apple ...