Unable to buy anything.

I changed my name earlier with MS points that I bought and Now i cannot buy more MS points. Whenever I try to buy a Games on Demand game, I get this Status code: 80153021. Any ideas?

Never heard of that happening before. Call Microsoft. They'll fix it.

I was also having this happen. What I did was back out of the shop completely to go to the dashboard, went back in and it fixed it. Wasn't until I backed out to dashboard that it would work for anything.

That's normal when there's an old credit card on file or a change of your gamertag, you have to login into your account in xbox.com and browse around your billing tab. sometimes xbox adds your old credit card as the primary.