Has anybody lost all there contacts while doing absolutely nothing to the phone? I had the contacts transferred from an iPhone X to iPhone 12 Pro Max and everything transferred fine and a week later I picked up my phone to check the time and that’s when I saw that nothing was in my contacts list!
Thanks so much for reaching out through Apple Support Communities for help with your missing contacts, and congratulations on your new iPhone. We'd love to help in any way we can.
To ensure we understand exactly what occurred, please let us know if your contacts were syncing with an online service, such as iCloud, Google, Yahoo, etc. If so, are you able to sign onto the website for the online service and view the contacts there?
If the contacts are visible directly on the website, you'll want to ensure that the option to sync your contacts is enabled on your device. This can be found under Settings > Contacts > Accounts.
If they aren't synced to an online service, is it possible that your missing contacts are present on another device? If so, which device? It may be possible to sync them from there to your iPhone.
The following guide explains how to sync contacts with iPhone using iCloud Contacts:
Set up and use iCloud Contacts
We're here for you if you've got any questions!
Have a great day.