Hi, you can actually earn Sofia's trust by getting her secret from Britney (caught her stealing from co-worker but choose to keep it secret). Your biggest mistake is you choose to enter Entertainment department. The game will only let you remove Rafael from his position if you choose to enter Business department. That's why Jiu will not offer you the DVD even though you have the money ($4000) because you don't belong to Business department.
At this point you probably need to restart the game and choose to enter Business department (Team A or Team B).