unfairly treated

Good day. I just want to complain about the bad service i received from the supervisor called Prudence from shell garage in Rosebank.i arrived at the station and asked the petrol attendant to pour petrol and wash my window,the attendant did pour petrol and asked me for cash,i gave him cash and asked him to wash my window.the attendant told me that he can't wash my window because he's tired.i asked for the manager and i was told i'm wasting my time as the manager too will tell me to wash it my self.the supervisor went far by saying that i'm black and i should't make myself white and that i must just wash the window myself.In other words,i was treated like im nothing because i'm black though i pour petrol here almost everyday.My question is this,does shell teach their employees to treat black people like their nothing?