To remove one email from contactable at setting
most respected dear sir
I had one Iphone 4 in 2014 so I sold it to someone then I forgot to sign out my iCloud that time so he added his email too and after some days that guy came to me to and told me to remove my Apple ID from iCloud and now his Apple ID is shown in my contactable at setting and I’m trying to remove but I’m not able it says YOUR EMAIL ADDRESS CAN NOT BE REMOVED & go to iMessage and face time.
so please help me remove that Apple ID from my contactable at email
thanks
iPhone X, iOS 13