Batman: Arkham Knight Standard edition has been removed from the Xbox store, and people who own the game digitally can no longer play it, however the premium edition is still on the store for people to buy, Xbox Support have responded and have said
“Alright, so I do see the special edition on the store at Xbox.com. But you purchased the standard edition, and at this time, we’re advising customers to head to Rocksteady’s site and contact them about the game being pulled from the market…I know Rocksteady pulled the game from all markets before because of the optimization that had many issues on their end for the game title. At this moment though, I would highly advise contacting Rocksteady, the maker of the game, to have the information sorted out to download a copy of the game you purchased.” .
It’s not the first time a game has been removed off the Xbox store this year. Just a few weeks before the game was released, Call of Duty Black Ops 3 was removed, though in that case, everything was removed from the Xbox store before coming back a few days later.