Hi, welcome to justanswer.com! My name is Mike.I am going over your question and I will be with you shortly.
You can't remove it completely but you can go to System Preferences / iCloud and just sign out. Unless you want me to help you figure out why it is not working for you? Let me know.
If you are satisfied, please kindly provide an OK or Above Rating - so I get paid. Keep in mind you can always come back to this page at any time regarding this question. Thanks!!
Did you do that?