How do I download or re-download DLC's like Son of Headhunter Pack 5 in Borderlands 2 for the Xbox 360? I try everything but its no use.
You should check your account history on the xbox to make sure it was associated to the correct account and then download it.
This is found in Settings -> Account -> Download History.
If it happens that it was associated to the wrong account by accident, as long as the first xbox used by the associated account is the same one you are trying to play the content on, everyone on that Xbox should be able to use the content but you'll need to use the original purchaser account to download it.