Former refugee Josie Ajak, 20, was on shift last week at the busy Gloria Jeans cafe in central Cairns when a female customer refused her assistance, instead requesting her to ‘get a white lady’ to serve.
Ms Ajak, who arrived in Australia as a refugee in 2004 after her family fled wartown Sudan, said she was "completely stunned" by the woman's reaction, having earlier greeted her with a smile.
"I was shocked but I responded very kindly, I said that’s fine and just moved her to the side and continued to serve the other customers," she told SBS.
"She sat there waiting, looking at me with very angry eyes. Every time I served someone she would make a comment about them [other customers] pushing in. She was really rude and asking rude questions while she was waiting, I don’t know what she was waiting for.
"After a couple of minutes she rolled away in her wheelchair while giving us the finger."
The incident was documented on Saturday in a Facebook post by her friend Jade Arevalo, which has received more than 500 shares,13,000 likes and hundreds of comments of disgust.
The post encouraged others to show support for Ms Ajak by using the hashtag #buyacoffeefromjosie, which has resulted in a huge wave of new customers to the store, who specifically ask for her assistance.
Despite calling the incident "absurd", Ms Ajak said it served as a reminder that racism should never be tolerated.
"The lesson here is treat everyone with kindness, when the lady said those words to me, I didn’t really feel hurt, I felt disappointed," she said.
"I felt sorry for her, to treat another human being like that, especially now, what does that mean for her?
"She probably had really terrible life, probably came across some really dark things in her life and maybe that’s why she treats people that way."
Ms Ajak was born in Uganda in 1996, two years after her parents fled the Sudanese civil war.
She recounted experiencing persecution and several near death experiences before arriving in Australia, a place she called her "safe haven".
The cafe manager told SBS the perpetrator was banned from the store and that "anyone who expresses any racist slurs would be told to leave".
The response on social media has been gaining momentum.
