SSFIV New Alternative Costume DLC Problem on Xbox Live
New SSFIV DLC ‘Ultra Challengers Pack 1’ & ‘Ultra Costume Catalog 1’ DLC has encountered a problem on Xbox Live.
You can still pay for the piece of DLC, but the issue is that you cannot download the DLC. Microsoft are currently looking into the problem and is attempting to solve the problem which has occurred.
Source: Capcom-Unity Blog