I'm also having this problem. I already chatted with the EA consultant who had no idea how to fix it and Microsoft rep online was even more no help. She even told me that the DLC was not yet available while we all gamers know this is exclusively available first on the Xbox One.
Please EA help!
Transcript from EA
info: Your approximate wait time is 0 minute.
info: You are now ready to chat with Vinay.
Vinay: Thanks for contacting EA Customer Experience, my name is Vinay. How may I assist you today?
you: Hello, I can't download the second assault DLC for my xbox one
Vinay: Hello, Ron how are you ?
you: I'm fine thanks
Vinay: I apologize for this.
Vinay: May I know the email associated with your account?
you: [edit: email address removed]
Vinay: Thanks for the information.
Vinay: Have you redeemed premium membership?
you: Yes I have. I have purchased it originally on my xbox 360 and It's already installed on my xbox one
Vinay: Okay.
Vinay: Are you getting any message when trying to download second assault?
you: The DLC doesn't show up on the xbox one as a downloadable content. It just says NULL NAME and there's no price. I've seen on other consoles on youtube that has the DLC, instead of NULL NAME, it would say SECOND ASSAULT.
Vinay: Did you check after restarting console?
you: yes
Vinay: Okay did you get any option to download it from ingame store?
you: the option is there but it doesn't say the name of the DLC. it just says NULL NAME and when you select NULL NAME. it doesnt do anything but exit you out of the in game store
Vinay: Okay.
Vinay: Would you mind if I place your chat on hold for couple of minutes to look into the issue?
you: of course. thanks
you: i dont mind
Vinay: Thanks for waiting .
Vinay: Please try this.
Vinay: Go to multiplayer then server browser then search. in search type DICE it will bring up second assault maps and instead of join now for the A button it will say download Second Assault.
you: Yes. It will say Buy DLC. Then when it goes to the in game store. The DLC is not available. It only says NULL NAME
Vinay: Are you getting install option?
you: No. It just exits the store
you: In the store. It says Battlefield 4 Premium (which its already installed) and underneath that is NULL NAME where Battlefield 4 Second Assault DLC should be. When I select it, it just exits me out of the store
Vinay: In this case you may get the dlc at a later dates. For some xbox one players who have premium on their account it is available but for some it is not. Don't worry it may be a server issue. You can get it in a later date.
you: That's not really helping. This is very frustrating. Thanks for your help anyway
info: Your chat transcript will be sent to [edit: email address removed] at the end of your chat session.
For some reason the transcript from Microsoft did not send it to my email