How come Apple doesnt have the ability to access information of when a specific icloud account was used to log into a specific device

I was going to loan my phone to a person whom was going to purchase it. This person turned out to be a very poor mannered individual, so I had to request my cell phone be returned. All said and done, this rude individual is now refusing to remove their icloud account from my phone. Why is it that Apple's resources can't pin point the moment the person had taken control of my phone and locate the time, date and account that had previously used it? Its seems to be.. they can access such information ... but... they're just not willing to help at all.

I cant even back up my phone from my itunes backup/restore saved log. It even shows that it's an earlier date than when the inconsiderate person hijacked my device!!!!