Right now, when the customer wants to leave the Chat, they probably just close the window using the browser's close command, i.e. hitting the X at the top-right, or hitting Ctrl-F4, Ctrl-W, or Alt-F4.

This makes it very unlikely that the customer will leave feedback (ratings).

The way Zoho SalesIQ provides for closing the chat is to hit the little + button, then hit the On/Off button. Only then will they get to the feedback/ratings screen.

I find it unlikely that customers will do that.

My suggestion is that Zoho SalesIQ provide a more visible/obvious way to close the chat window.