why does my apple account say my iphone is not linked but my iphone is saying otherwise when trying to activate?

First time Apple user here!! So please help me to the best of your knowledge if you will! I am 65 and not very tech savvy you can say LOL!

I am sending my iPhone in for a warranty service repair and I was testing out logging out of my device to make sure that I know exactly what to do and how to do it for when the replacement phone arrives and I have to send this one back . My phone is now telling me that I am active on the ‘Find My Iphone’ app on account via phone but the app is also ‘Disabled’ however when I look at the account online it doesn’t seem to be the case and it says that my Find my IPhone is on?? I am worried that when I send the iPhone back it will say that it is still active via ‘Find My Iphone’ on my iCloud account or even worse the phone itself! How do I go about troubleshooting this problem so I do not have to worry about it the day I am supposed to send the other device in?

Thank you in Advance.