How do I get the F&F Car Pack when I purchased the F&F Films?

I saw a promotion that when i buy the Fast and Furious Collection on Xbox Video I will get the Car Pack for Forza 6.
But when I look for the car pack it says that I still have to pay for it?
So my question ist, how do i get it for free now?

Thanks in Advance!

The promotion is for Dom’s Charger only, not the full car pack.—DLC-and-Editions-List.aspx