"Invoice for no service provided in Emergency Department"

My relative came over to Melbourne with her husband a few months ago. While I was at work, they visited the Box Hill Plaza and my relative had a fall and knocked her head against a dining chair in the food court. She was bleeding profusely and being a tourist here, they do not know what to do. The Box Hill Plaza security came and offered them to go to Box Hill Hospital. So, they went to the Emergency Department and had paid the cashier $440. They were told to wait in the waiting room.

After 3 hours of waiting, there was no service provided. No one came to talk to them. No one seemed bothered or concerned. Feeling the pain and bleeding for the 3 hours waiting there, she decided to cancel her appointment. She approached the cashier and demanded to have her money back and to cancel her appointment. She got her money back and went to a specialist nearby to have her bleeding forehead attended. Within 20 minutes, she was attended to and was given 8 stitches. This is the service that we expected as this is classified as an emergency.

Now, I received an invoice of $440 from Eastern Health, trading as Box Hill Hospital, for my relative. 

OSV110 - Facility fee and treatment emergency attendance - $440

In fact, there was no emergency attendance nor treatment nor facility tendered to her. Why is she getting this invoice?

She has been given 7 days to pay this account!

Moreover, there is a threat from the letter that - this may result in referral to a debt collector with additional costs.  

Can someone please provide me with some answers? I believe that the cashier did not cancel the appointment in your computer system. Thus, the invoice was generated.