Hey sprocket, make sure you check your emails from Ubisoft as well. If you still cannot find it, please submit a ticket with Ubisoft Support. They will do their best to help you find a solution.
I submitted a ticket and it says wait 48hours, Kinda not the point of 3 day early access. I am online with Chat and they say I should have gotten the code, to check spam. It isn't anywhere to be found. I never got my beta access either even though I have a receipt showing I purchased Ultimate edition. Dispute the credit card purchase and re-do it?