DLC - artorias of the abyss expansion for dark souls

About a week ago I bought dark souls from an amazon seller and played it on my xbox one with no issues. However I was notified I had the artorias of the abyss dlc for some reason which was confusing since I never purchased it. I checked manage game add-ons and I indeed owned it and just shrugged it off and ended up beating the game. The next day after I tried playing on my 360, however it said something along the lines of "cannot located artorias of the abyss dlc, reinstall so you can access this character". I checked everywhere and I just accepted the fact that I owned artorias of the abyss on xbox one and for some reason not xbox 360. Fast forward to now, I haven't played the game since and all of the sudden I'm hit with the same message I recieved on xbox 360 about "cannot locate artorias of the abyss dlc, reinstall to access this character". I turned the game off and turned it on and got the same issue. I clicked on manage games and add-ons on dark souls and the dlc was there, about 312 mb if I recall correctly. I uninstalled all dark souls local data in an attempt to reinstall it all and fix the problem. However I was very confused to find that afterwards I did not own artorias of the abtss, its also currently not available in the xbox one store, and I cannot reinstall it or find where it's located. Now I don't know what to do, I feel as if my issue is some sort of bug because none of my problems were mentioned in the non contact guides. I don't know what exactly to ask other than what happened and how do I get my DLC back?

:)