Totally get this... you can contact support via https://support.google.com/stadia but they will likely tell you it may take 3-5 business days and to contact them again if you still haven't received the code by Friday.
DID YOU FEEL THAT?!?!?!?!
That's the Earth losing and gaining momentum at the sway of the entire Stadia member-base shaking their heads in disgust at the same time to this insane situation.
....whoa, there it goes again.