Hi Claire,
I'm sorry that Max is glitching on your TV. I recommend ensuring your TV is up to date with the latest Firmware. Go to Settings> Support> Software Update.
If this does not fix the issue, you may need to delete and re-install the Max app.
Finally, please know that the CU7000 TV has a built-in app store with hundreds of apps available to choose from. Go to Home> Apps> Search and type in the app you are looking for.
I hope this helps!
~Samsung Advisor