So, I have also had the issue of buying movies on the app since the NXOE. So, I decided I'd buy it off the website and not the app.
Now, I have done everything. Deactivated my devices on Vudu, Uninstaller numerous times, hard reset and I get the same error. "Sorry, VUDU movies isn't available right now. Please try again latet. For more information, go to http://www.xbox.com/status"
I'm at my wits end. I know it's part of the NXOE bug, but it's a huge one as VUDU is my main source for movies.