No petrol filled in my tank!

It is with great sadness that I'm writing this complaint as I have experienced this before at a Sasol on Malibongwe drive but it was quickly corrected by the attendant! Today 02/11/2017 at around 06h05, I decided to fill up at Sasol Schurveberg on the R512, Hartebees as there's a lady i'm collecting there. I filled my car with R100 of petrol as I had 113km which I thought let me just put a R100 and make a full tank on my return when I'm not rushing. The attendant who assisted me was Duster and I paid him cash. As I drove off I realised that my gauge was not moving, I then decided to make a U-turn, as I turned I realised that only then Duster was going to the cashier window, I stopped on the pumps and without saying anything to other attendants, they said to Duster, "the car did not fill up Duster" Duster came with a slip to me and said if he did fill my car up, the slip wouldn't come out had he had not put fuel, I then said but it can't be that my gauge doesn't move after so long, (my car is still idling at that time), I then asked, till what time is he working as I will come back to query this with him later, the lady I drive with said they change shifts at 6pm, so I said I will come back later, I then drove off. After driving less than a KM I decided to have this reported to the manager, so I made a U-turn again. I got him (an old white man-didn't get his name), I explained to him what happened and he said there must something wrong with my gauge, and I said to him, its funny that my gauge decided not to work after filling up at his garage. He then said he can show me balances of his fuel levels and income that they balance, bla bla bla! I then said to him its fine I will drive to Randburg, but will be back later, and on my way to work, my petrol gauge was definitely working as my fuel count was getting lesser and lesser. As I arrived to work, my gauge was on 89KM. I then decided to give the manager a call to clear this and unfortunately I was told he has left, I told the lady what happened and she took down my details and said she will ask the owner to call me. I'm rather shocked because reading at other old posts, this seems to be happening a lot at Sasol garages. R100 might not be a lot of fuel, but how many people have actually been ****** off fuel without noticing? I want my R100 fuel and would rather loose money having this solved in the process because at the end of the day, attendants must be taught not to underestimate Sasol clients, this is about me loosing out but at the end of the day I will be helping/saving the next possible victim. I work in the Retail motor Industry and will see to it that this is taken further within the fuel Retailers' association.