Same thing happened to me. I unlocked it, but when I go to my awards in the avatar editor, they just display a “!” where the items should be, and I can’t select them.
One workaround I figured out was using Smartglass and editing my avatar there – the items were available to use (and I’m using them now). If you don’t have a phone/tablet that can run Smartglass, you can probably edit your avatar on the xbox.com site and do it that way as well.
www.XBOXAvatarGEAR.com 
September 19, 2012 at 5:26 PM
this looks pretty nice.
March 26, 2013 at 12:34 AM
Mine ain’t working, anyone else have problems with it?
April 10, 2013 at 7:45 PM
Same thing happened to me. I unlocked it, but when I go to my awards in the avatar editor, they just display a “!” where the items should be, and I can’t select them.
One workaround I figured out was using Smartglass and editing my avatar there – the items were available to use (and I’m using them now). If you don’t have a phone/tablet that can run Smartglass, you can probably edit your avatar on the xbox.com site and do it that way as well.
April 28, 2013 at 5:37 PM
This whole Jet Set Radio avatar award is a joke and it is glitched. There is no such thing. No one has the avatar awards. Was a April Fools joke.
August 11, 2013 at 2:12 PM
Same thing happened to me,has anyone unlocked them for use?