R6000 too much swiped at Sasol garage "by mistake"

On Monday 15 October our truck went to the Sasol N17 Plaza to fill up on diesel. When he was done he had put in 196,56 liters of diesel. Thus with the current price the amount being R3,319.90 at this stage the pump attendant swiped the card after my driver told her the amount wasn't right for a staggering R9,319. 90!!!! I climbed in my car and went there immediately to sort it out. On my arrival I found my truck and driver standing there with no one in sight to help. And despite the fact that I found it unacceptable to make such a big mistake there was no sign of my petrol card no matter who I asked. Eventually someone said that my card was with the supervisor but they didn't know where he was at that moment. After a while the supervisor came out from behind one of the containers. He apologized for the inconvenience and gave me my card. The difference in the actual price and the swiped price was R6000! They eventually did a refund on the card. Today however the refund is still not reflecting on the account and it is completely unacceptable for me as I have not made any mistake and I have to suffer the consequences. I tried phoning the contact numbers I could find and they are all out of service.