I just purchased the Collection 1 Downloadable content for MW3 on PC.  I purchased through steam, and I checked my bank account and the $15 was charged to my account.  Steam them updated COD MW3.  After updating I launched MW3 and it would not let me play on the DLC game types.  When I right click on MW3 in my steam library and go to view downloadable content it says that I do not have any downloadable content.  Thank you for helping me resolve this.