They said they would get back to me within 24 hours. It's been 2 days.

Microsoft support team said I'd get a response within 24-48 hours it's now been nearly 3 days since I posted this. Honestly how did this even happen.

Just an update on this. E.B. Games has been in contact with me on the issue and had said that their District manager would contact me to resolve the issue within 24 to 48 hours. So far it's been 4 days since that statement was made by them and still no contact.
That pretty much says it all I think.

Yup GT5 is the only game on a console with a TRUE 24 hour race along with day night cycle and weather. Grid has a 24 hour race but it is only about 30 minutes if I remember correctly. You could set up a 24 hour race in Forza 3 or Forza 4 but like you
said it would have to be hot laps. If you tried this online in any game you would probably get disconnected for sure within a 24 hour period.

So... should I ask for a new code? Customer support told me a few hours back that they will contact me in 24 hours and right now I am currently waiting.

If they've said they'll get back to you in 24 hours then just wait.

If within 24 hours you hear nothing then contact them again.

As you got the code from CD Keys there isn't anything anyone from Microsoft can do i'm afraid.

Well last update they had it back within 24 hours; As it seems to be roughly the same issue, I would imagine normal service will resume within the next day or so.