Different customers treated differently!

The Pro shop Woodmead service quality depends on your race. James, the person working at the change room has no etiquette. I walk up to the change room to try on some clothing and he is busy on his phone. All he says is "full". While waiting another person walks straight past me into the change room. James says at a very low volume "Sir it is full" but does nothing else. Someone comes out and the customer goes in. James refers to this person as Sir though because he is of a different race. I then tell him to do his job and an argument ensues. I did speak to the manager afterwards about the incident and it seems like the first response is to pacify the customer by giving them something for free instead of addressing the underlying problem of different customers being treated differently. I was promised feedback from the manager and still await a response.