Why does my iPhone keep signing in as a macOS X 10 when i don’t have a Mac

See this Apple article: Check your Apple ID device list to see where you're signed in

Check your Apple ID device list to see where you're signed in - Apple Support

Remove all devices that isn't yours.

I keep getting the same message. I also was told by an apple adviser that I had a 5,6,8 I phone connected to my new iCloud email. She was the only one who has noticed and removed it. Even though when I would look in my apple account I wasn't able to see it. Has anyone ever had this problem