There are many instances where Alexa may not respond to your commands.
Please check the points below for help in this matter:
Make sure your device is paired to your device. You can check if they are paired on your Alexa App's 'Enabled Skills' section. For information on pairing your Alexa to your Better TV device, please click here
Make sure your Alexa device is not on mute
When you are commanding Alexa with voice, make sure a blue ring is seen in the top left corner of the TV screen. This means that Alexa is listening for a command for your device
Ensure that your are saying the correct commands. For more information on available Alexa commands, please click here