I was banned yesterday for a week… all i can think is its coz of my bumper sticker i made… i made one saying “im only speeding coz i need to poop” it had about 35 downloads… next day i have the banned msg. Cant believe i was banned over this lol. There is bumper stickers full of swear words that havnt been banned… yet i got a weeks ban!! 
Apologies for your frustration, however you should contact Turn 10 at forzafb@microsoft.com
Bans or enforcement of Xbox LIVE’s Terms of Use and Code of Conduct are not discussed on the forums.