Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
How did you purchase the subscription? Was it through the Roku device or did you purchase a subscription through the channel provider directly? Did you see the NBA channel previously on your Roku device?
With more information we will be able to assist you further.