Write SQL query to solve given problem: Which free app has the most Negative comments?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T1.App FROM playstore AS T1 INNER JOIN user_reviews AS T2 ON T1.App = T2.App WHERE T1.Type = 'Free' AND T2.Sentiment = 'Negative' GROUP BY T1.App ORDER BY COUNT(T2.Sentiment) DESC LIMIT 1