Check your bill carefully

Used their valet service at Cape Town International when I went away for the weekend. The parking and service at the location was top-notch, car was clean and no issues so they get 1 star. However, I ended up paying twice for my parking as the accounts department is a shambles. I received an invoice before the time which I thought was for the deposit to secure the booking, so I paid it via Payfast. I then paid what I thought was the balance when I collected the car. But because my first payment hadn't reflected I ended up paying the full amount again. So I realised afterwards I had actually paid IN FULL TWICE. It's my own fault I was tired and didn't check the bill properly, I just wanted to get home. Anyway I have been trying to get the second payment refunded now for over a month. I am not getting any resolution. Just excuses.