Hungry Jack's Australia review: drive through order

I came through the drive through at Hungry Jacks Reynella on Sunday evening and put an order of burgers and drinks
I also ordered 3 stunner meals which they somehow knew but it came off there screen or something happened and when I paid I only paid for two
The workers put the drink and the Cornetto for the third meal with the rest of the order and then when the screen dropped the third order disappeared before we paid
I understand I only paid for two and still received part of the order but when I rang to explain the store had made a mistake I felt the manager was like well you only paid for what you got . Yes I did and when he didn't seem bothered that they had made an error and that I now have to drive over 10km there and back from the store to complete the order that I didn't get wrong
I did drive back but went on the other side of the road to MacDonalds
Kind regards