How to change the random phone number linked to my Apple Account?

The phone number associated with my Apple ID account has been changed. Randomly. I have no idea who’s phone number it is It includes just the last two digits. I have no access to the App Store iCloud, etc. I reset my phone to factory settings. I thought that would help. my email is the same. But that random phone number is still there.Can anyone help?

[Re-Titled by Moderator]