the 6months free for Spotify only works if you've never had Spotify premium before. you log in or create and account and it will prompt you to redeem your 6 months. as for youtube, again only if you've never signed up for premium. you go to get youtube premium in the menu and it will prompt you to redeem your premium
I would recommend calling into 1-800-SAMSUNG and ask to speak with our promotions department, they will be able to look into this further for you. Thank you for being the best part of Samsung!