HALO 4 Code. Where is the link for contact us

How could I get the Halo 4 code resent to my xbox mail account?
The code sent on 12/05/12 was not activated. The code needs to be resent my user name is sandmite as the mail was deleted.
Can someone from here pass on the information to the correct personnel?
Could someone respond and let me know who I should contact?

Thanks sandmite