The usual cause is not letting the DLC download all the way. Double check that they show unlocked on your account, and see if you can manually set them to download. Make sure you are online of course when you start the game AFTER fully downloading the game. If that doesn't work, the try a repair of the game, as sometimes it still doesn't want to download. Sorry, I am a PC player, so I don't know any specific ways for the PS4. A few times I have seen people who bought the game in a physical format, and they didn't actually enter the DLC codes, just the game codes. So if you bought the game from a store and got a box and disc, double check you have redeemed the codes and make sure you are still on the same account as when you redeemed them.