You'd have to have created one to purchase it, as strategic packs, memberships, etc. are tied to accounts.
I think this is incorrect, as when you play from the phone you can do SP levels without ever creating a user. (warzone makes an account for you, but the player doesn't put in username etc.). You can still buy stuff too ofc. Either way, as Fizzer has already said, when you run into issues like that of OP, you contact him and he can help you out.