Red Dead Redemption, Legends & Killers XBox 360- download won't play

[hurkleho]

Hi, I downloaded the Red Dead Redemption game add on 'Legends & Killers' from the Xbox Live game marketplace. When I get to the start up screen, it won't allow me to play it, the only options are to exit or add a Rockstar code. I've been on the Rockstar forums and it seems alot of people are having the same problem, but Rockstar are denying there's a fault. Very frustrating as I'm out 800msp with no refund. Hope someone can help! Julie