Can I close a chat as no one is getting back to me?
If you don’t need help anymore you can send a message saying that, but you can’t close it.
Unless you mean can you close the app while you wait? In which case yes, you’ll get a notification when they reply
I’m not sure what the current waiting time is but it should have said after your first message was sent
You can’t. Best to call them and ask them over the phone, they can sometimes assist or escalate.