@Sissy13 So you are saying you never received a message asking you to agree to the guest cancelling?
If that is the case, then you shouldn't have any cancellation in your stats. And in fact, if it had gone down as a host cancellation, then "Host cancelled this reservation XX days before check-in" would appear on your review page, which it doesn't.
So this sounds like a tech glitch to me. Whether you want to spend time trying to get to the bottom of it with CS or not is up to you. But it will affect your ability to get Superhost until the April assessment next year.