Thank you for contacting Turn 10 Studios. Due to the volume of mail we receive, we cannot individually respond to all e-mails sent to us. If you have a question about a Xbox LIVE or Forza Motorsport Terms of Service, please see the following links:
Hmm, stole your money, eh? That sounds a little bit harsh, wouldn’t you say? If you looked into it any, Xbox is currently experiencing limited service issues which may have something to do with this. Second, Turn 10 creates the DLC, but it is Microsoft which posts it to their Xbox Live service and ensures that games can correctly read what your Xbox Live Profile has purchased.
The issues you described are not the fault of Turn 10, nor can Turn 10 do much about it. Your best bet is to contact Xbox via chat, e-mail, or by calling (in the U.S) 1/800 4 MY XBOX. Alsom it wouldn’t hurt to check your download history on Xbox.com to make sure the items appear there.
Sounds more like a profile error. I am having no issues with my Forza 5 DLC. You can try what I wrote above, or try re-downloading your Profile - just make sure you don’t delete your gamesaves.