"The long wait at Uveitis clinic and cashier behaviour"

We had an appointment in the morning for the Uveitis Clinic however we were still waiting to be seen by the Dr after 5hours of waiting. Multiple other patients and families were quite frustrated and the remaining doctors and nurses there did apologise for the long wait. A number of doctors did look like they left for the day with their bags so there were a lot of empty rooms.

It would be helpful if the tv screen showed a list of patients waiting to be seen in order with a ticket number just like RTA so that patients/families know roughly how long the wait is and also if they need to rush out and grab lunch. Because it was a morning appointment a lady came around with free sandwiches for my family which was appreciated but my family had to go to the cafe to get more lunch as they were still hungry and that adds to the risk of them leaving whilst their name is being called out.

Additionally, every time we have an appointment at Sydney Eye Hospital, because my parent has a concession card, i need to go to the cashier to show:

a) parking ticket

b) concession card

c) appointment letter for parent on that day

We have been going to Sydney Eye Hospital for nearly 2 years and the cashier always takes the letter to enter it into the system but also to keep and they don't hand it back. And every time i have to say i need the letter back for our records. The cashier then rudely (it seems without exceptions) says, you have to wait!. And then types in something into their system then hands the letter back without saying anything. It is my parents letter that i keep within their health files and i don't believe the cashier should be keeping any appointment letters with our private details.

I went recently and it was around 3.50pm and I felt the cashier rudely said they are closing soon and they have many things to do after i asked for the letter back which they had taken and put in a pile, and in a huff they entered the details they needed then handed the letter back without saying anything. The cashier had another patient (elderly) after and before it was 4pm (3.56pm) they half-closed the shutter.

Number 1 = it is the cashier's apparent job to enter details into system

Number 2 = it is not the customers fault that they need to enter the details into system

Number 3 = if they seemingly hate their job that much, leave.

Every time i leave Sydney Eye Hospital i am infuriated by their rudeness and leaves me with a bad taste in my mouth, every time. If they require to see the appointment letter, I believe it is their job to enter whatever is needed and hand it back to the person. Why on earth would a cashier need private appointment details on a physical letter actually kept at the cashier to validate parking??? That seems unnecessary. 

Instead of telling the customer, you have to wait!, so rudely, why doesn't the cashier just do their job properly and quietly without abusing the customer and tell themselves "okay i need to fill in what is needed and hand the letter back the the customer" or even say to the customer "i just need to enter the details, one moment" and hand the letter back to the customer. I feel their rudeness is unnecessary.