I ever try to report post but it still said : You have reported 0 posts with 0% accuracy
Was it being calculated by system or by moderator ?
Did you press submit? Whenever you report a post the number of reported posts will go up, but the percentage will only change when a report has been handled. However, it sounds to me like you haven't pressed "Report to moderator" but, haven't pressed submit on the page which follows. It's below the input box.