You must own both TDB and HoW, on the account you wish to purchase the digital download version of TTK. Having access to another account's copy of the year 1 expansions, via digital rights management, is not sufficient. If you do own both year 1 expansions on the account, try restoring your licenses: https://www.bungie.net/en/Help/Article/12181 Next you may try "purchasing" the two standalone year 1 expansions from the marketplace. If you own them on your account, they should be listed at no cost. If none of this works and you do own both expansions on your account, the next step would be to call Microsoft, as they own the store, your account, and the licenses attached to it.