KF8 outcomes/ KA returns

I was under the impression with a KF8 if you use it for a day or two, you could return it and called customer care today and I said no! Unused only. Which is fine for me cause it’s still in the box. So just wondering how others are enjoying theirs? All the reviews and everything seem pretty darn good! I just still don’t know how to expect you to like something before you try it on…