Lo he probado, a ver si me lo envian.
Un saludo.
EDITO: Esto me han respondido al segundo:
Hi,
Thanks for contacting EA Help.
We're sorry, but we don't have any Rocket Arena codes left for Xbox One.
If you like, you can contact us again to request a code on PC or on PlayStation 4.
You can still join us in the arena when you buy the game in the Xbox Games Store.
Happy gaming,
EA Help