Refund and feedback

I rented a car from 04-07.05.2015. I was asked to pay R 1500 and it will be reimbursed once the car is returned. I was told it would be in my bank account the same day if the tank was full. If not, then it will take about 3-4 days. I accepted the conditions as explained to me and took the car back using a total of 374km and just about a half a tank. I did not refill the car. When returning the car, the people that assisted me was not helpful at all. I called on Monday, 11.05.2015, to enquire when and how much money will be refunded, but was told just to wait. 'It will be in your account on Friday or Monday for the latest as it takes about 7 working days', I was told by someone at the branch. The phone rings long there and soon as someone answers, they cannot wait to get you off the phone again. I called again on Thursday, 14.05.2015, and was told to wait until Friday to enquire, even though they could not find the any details on the system. I spoke to customer service, Billy, the branch Manager and Craig van Niekerk. They overcharged me on petrol and today, 18.05.2015, I still have not received my money. They said there were issues with FNB over the weekend. I am very up upset.