I had a similar issue years ago when I switched credit/debit cards. I ended up fixing it online with my computer and not the Xbox. I had to delete off the old credit card, add the new one so it was the only one, and then everything worked fine. I would also try deleting the Netflix app off the Xbox and reinstalling it after you've done the fix (if you haven't already). If that doesn't work, I dunno Check FAQ's on Netflix maybe or call them?