SASOL PETROL STATION (K8 SOUTH) POURED AIR IN MY CAR.

I am a consumer. On the 01 October 2018, i went to Sasol petrol station (K8 South)to fill in the fuel, i requested R 500.00. fuel. After the petrol attendant was done filling in my car, the level of the fuel in my car remained the same, the fuel level did not go up. I immediately called the petrol attendant and the manager to assist as it seem as if nothing was poured in my car and i paid R 500.00. as i was not assisted at the petrol station, i called Sasol and they indicated that they will send a technician to the station, the technician went to the station a week after my incident, and the report came back saying that there is nothing wrong with the pump, maybe its my car with a problem. My concern is that if the technician went to the station on the same day or the next day, they would have seen the problem. After 2 days i poured petrol in my car and the level of the fuel went up, to show that my car do not have a problem. Please assist by investigating this matter further as i have lost R 500.00.