I found calling support was best. Politely let them know that you pre-ordered Halo Wars 2 Ultimate but you haven’t received the HW:DE code yet.
Let them know that on the 343i forums it says that THEY need to verify your pre-order eligibility and generate you a code because all of the codes were sent out already.
5 minutes later I had my code!
Who did you contact?
> 2535461420852747;2:
> Who did you contact?
Xbox support by phone.
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> > 2535461420852747;2:
> > Who did you contact?
>
> Xbox support by phone.
Just tried this, didn’t work 
Need to ask for a manager I’ve heard or make a post on Xbox forum. You also need to be in the group that pre-ordered before 20th december or have had 7 to 10 days pass since pre-order.
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> Need to ask for a manager I’ve heard or make a post on Xbox forum. You also need to be in the group that pre-ordered before 20th december or have had 7 to 10 days pass since pre-order.
Why 7-10 days for a digital code I wonder…
I just pre-ordered today as well so I’m waiting on my code. I’d like to just start played de right now. I mean I just paid for it
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> I just pre-ordered today as well so I’m waiting on my code. I’d like to just start played de right now. I mean I just paid for it
Same, I pre-ordered yesterday thinking I would be able to play DE straight away, bit unfair really.
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> > 2533274951798334;7:
> > I just pre-ordered today as well so I’m waiting on my code. I’d like to just start played de right now. I mean I just paid for it
>
> Same, I pre-ordered yesterday thinking I would be able to play DE straight away, bit unfair really.
It does actually say you have to wait 7-10 days, though in my opinion it is not shown well enough.
Either way - since you are here on the forum it means you want Halo Wars 2, and you want HWDE so you really don’t have much option besides waiting xD