Very upset

On 22 November 2018 I went to Caltex Fernglen Port Elizabeth to put in aR100 petrol. My fuel light was already on and my cas showed that ot could do another 61 km. As I had my 2 kids in the car I did not notice what the petrol attendand did but noticed that the previous client had also put in R100 petrol. I dis not look at the fuel pump to see that it started from zero. The attendand stood and looked like he was filling my car with the petrol. I then handed my card to him paid and drove off. Before I left the premises I shaw that there was no change on my fuel gage. I made a u turn and requested a cash slip whereafter I was handed a hand written note. I was furious and asked to speak to the manager. He was not much help at all. I dropped my kids off at school and phoned the manager and requested that he looks on their system whether a R100 was filled at the time that I was there. He took my number and promised to phone me back. When I left work at 16:30 I was reminded if my bad experience that morning and that the manager still had not phoned me back. I phoned him when I got home and he had an attidude with me and my fiance. He thenphoned us back about 45 minutes later to say that he looked in the security camera and that it looked like the guy was putting petrol into my car. I am really furious as a similar experience happened to me at another Caltex branch and yes it was my mistake for not looking clearly what the attendant did but I really expected the manager to handle the situation better. All that I wanted was to find out whether the fuel pump registered at the timw that I was there that the petrol was put into my car. But nothing. I am very dissappointed and only use Caltex as I earn Ucount rewards. I would have thought that the matter could be resolved amicably but unfortunately this was not the case and I am out of pocket of R100. Which is not alot but still I feel that I was cheated.