I bought the game but none of the characters are showing up beside the free one maya. My windows is up to date. i have the xbox hub. I see all the character dlc content under the section This app will not work on your device
this may be better suited to the official bug reporting thread. https://forums.ultra-combo.com/t/official-ki-bug-reporting-thread-season-3/7456
tagging @rukizzel or @developers might also be able to help, but I personally don’t know how to solve this problem.
Also welcome to the KI community 
sorry your first impression is like this though. If you have any other questions, most anyone on the forums will be able to help you.
try this, sign out of the store and xbox app, and launch the game, when it prompts you to login with the account, do so.
Sometimes the game needs to be re-synced. Hopefully this will solve the issue if not, then I am sure the @developers or @rukizzel might be able to help
and welcome to the KI community.