Calls only appear with a label after the number has been verified to fit a specific category. When a number has not been verified i.e. a valid number, they will appear uncategorized. If you received a spam call that was not categorized, you can help the community by reporting the number to the FTC inside the app. By doing so, said number will get reviewed and eventually enter a category in the future (thus preventing other users from receiving the number as uncategorized).