Contactable Phone Number (suddenly unknown number added by itself)

To edit your list of trusted items refer to the section: About trusted phone numbers and trusted devices in the document Two-factor authentication for Apple ID - Apple Support

1) Open the Settings app

2) Tap your name at the top

3) Tap "Name, Phone Numbers, Email"

4) Tap "Edit" next to "Contactable at"

5) Tap the "-" next to the number you wish to remove.

6) Tap "Delete" and then confirm your choice by tapping "Remove".

You can only delete a number this way if it's not the one being used for Messages and Facetime. If you don't see the option to delete the phone number, and instead see a warning that the number is being used for Messages or Facetime, follow these steps:

• Tap the back button until you're back in the Settings menu.

• Scroll down and tap Messages.

• Tap Send & Receive.

• Tap your Apple ID at the bottom.

• Tap Sign Out. Once you're signed out, tap the back button until you're back at the Settings menu, and then tap FaceTime.

• Tap your Apple ID under "Caller ID" and select Sign Out.

• Now that you're signed out in both locations, the old phone number is no longer associated with your iPhone.