Hello there, c-s_pin. Try using Alt+Tab (Windows) or Command+Tab (Mac) to cycle through your windows. QuickBooks chats often launch in a small pop-up that tends to hide behind your main browser window. It's also worth checking your email inbox for a session link or follow-up messages from the chat support.
If you still can’t find it, you'll need to re-initiate the chat. A quick tip for when you get back in, ask the live agent for a case number immediately. That way, if you lose the connection again, the next person can pick up right where you left off.
We'll be right here if you require additional information about this.