Ubi has send me the official word on the RSV Black Pack (which went MIA earlier this week) and it is good news:

‘Tom Clancy's Rainbow Six Vegas Black Pack Downloadable Content for Xbox 360 Live was originally intended to be free content for the fans of Rainbow Six Vegas. We apologize for the error. All players who purchased the Black Pack will be reimbursed automatically.* The Black Pack will be posted Saturday June 30th and will be free of charge. Also, as a token of our appreciation for the Rainbow Six community, we are making the Red Pack free as of Friday July 6th as well. Thanks for playing and we hope you enjoy this free content.’

Make sure your account information is up to date so we can properly apply the credit!

As I understand it the content should go out after 0300 PT.

Edit: * All players who purchased the Black Pack will be reimbursed automatically within 8 to 10 weeks.