This particular set of in-game armor is only available as a gift from Microsoft or Bungie.
The victim claims that they have attempted to contact Microsoft, but ended up being hung up on after several transfers throughout their customer service center.
You can read the full details of the whole affair on the player's clan forum. While interesting, and entertaining at times, it's rather long (18 pages at the time of this writing).
According to the hacker, who makes an appearance on the forum, all it took was one phone call and 15 minutes to get access to the account.
After going through the thread, it appears that the hacker's main motivation was to upset people.
With any luck the player will get another set of armor for Microsoft of Bungie, and probably more importantly, put a little pressure on Microsoft to put measures in place that prevent this type of thing from becoming a regular occurrence.