Maybe you fixed it, as when I chat with your bot I get,
> Thank you very much
> Okay see you
The reason your bot is repeating some questions is it has no response and no default response.
You should add a default response (such as "Sorry, I do not understand.").
In general never add common words like "you" as a keyword (you can put it as a required word).
When the bot say "I understand...." this response is coming from the "Understanding" script. If you don't want these responses then delete that script.