Ripoff at the pumps

I contacted Caltex via their website to have the pumps checked at one of their service stations but I haven't received an acknowledgement of my request or anything to say they are interested in investigating. My vehicle fuel tank specification is 58 litres, I had more than a quarter tank fuel but when I topped up at a Caltex filling station, the pump read 56.57 litres. This is highly improbable, hence I asked Caltex to investigate. Caltex has been my choice of filling stations for over two decades, but needless to say I won't be using them in the future. I will also encourage my family and friends not to use them. Obviously Caltex doesn't care about its customers!