Bad customer service

I went to 24 Spar, New England today, I stood on the queue for electricity as there was no one on the till until I went to the till for grocery and complained that I am not attended to. I was told to go back to the electricity till. When I went back, a lady called Cebo who was there when I complained about standing in the queue decided to assist someone who came after me. When I complained again she said she did not see me waiting before. But she only came to the till because I complained of not being attended. I then asked her whether she wont apologise, oh she was was too high for that and she ignored me while assisting someone else. The supervisor, Thokozani came and I told her that i do not understand why I am not being assisted first when I went there and complained and on top of that no apology is being offered. Unbelievably Cebo said she cant apologise while serving another customer, the same customer that came after me. Thokozani apologised on her behalf, that is just crazy. She was busy explaining to Supervisor what happened, still no apology offered even after she finished servicing other customers she wouldnt dare apologised. I do not like the way she treated me. It was the first time I see someone that rude in that Spar. Just bad customer experience. I had to ask for an apology and still did not receive it, I am not sure whether anyone can believe something like that happens.