First, per TibiaQA guidelines, flags should not be used to indicate an incorrect or incomplete answer. Even if you are certain that an answer is completely wrong, you should not flag it. Instead, downvote the answer and kindly explain why the answer is wrong in your eyes.
The Very Low Quality flag was introduced to mark posts that have so many formatting, gramatical or wording problems, that it is unlikely someone will ever be able to edit the post to the state where it can be understood by the majority of the community. A good use for this flag is also marking non-English content.