Just talked to Xbox support. They claim emails will continue to be sent over the course of the weekend and Monday, possibly into Tuesday. They said if you don’t still have an email by Tuesday, to contact them again.
This obviously becomes more complicated if there’s a problem with the email address it actually gets sent to. But if you haven’t yet received a code and the email address associated with your Live account is current and accessible, there is still hope you’ll receive a code soon.
Apparently.