OK, let’s walk through the steps.
The prompt for the composite entity generates a button, and when the user clicks on it, then the payload string is sent to the bot platform. All this does is save the user typing, so the same utterance can be sent if the user typed the same thing or something different.
So for the payload to be interpreted in a List of Items entity then it must exist as a synonym for a choice. You only need one choice (so ignore any warnings that bot builder might display - it is overly cautious!). Now as I described in my previous message, a payload of “n/a” doesn’t quite appear as that to the entity and how you can mitigate it. One or all of those tactics will work.
I can see on the message node that you are just trying to output context.entities.Entity0005. This is the composite entity and so this is a JSON object - all composites are objects even if only one subentity is actually identified. So you may want to expand this to context.entities.Entity0005.EnterNA, or use script to print(JSON.stringify(context.entities))