The BB6 contestant became riled up earlier this evening after she thanked the chefs for the spaghetti and meatballs they had prepared for the house, but received no reply from the pair.
Standing up to address the group, Makosi stated: "People in this house don't know how to take compliments. When somebody says 'Thank you' for something, not saying 'You're welcome' is like throwing your 'Thank you' back in their face."
When Chantelle suggested that Preston and Ulrika were just being humble and joked that Makosi must be continuing her secret mission to make herself unpopular, the African housemate snapped: "Are you saying I'm being mean? It's not a funny joke."
Storming out of the kitchen, she added: "In this house you can't have an opinion, you just have to sound like everyone else."
Later, Makosi continued to dissect the argument with a bathing Nikki: "I don't think it's rude though. I think everybody's being too careful. I really meant [it] to Preston. I've noticed on two occasions I've said 'Thank you' for something, he's sort of not taken the credit by saying 'You're welcome'... there is nothing wrong with taking credit for what you've done."
"A lot of people lack confidence 'cause they actually think low self-esteem is humility," she continued, before turning her attention to Chantelle's comments at the dinner table.
"I did not expect Mrs Preston to talk for Preston 'cause it made me feel like she thought I was picking on [him]."
Realising that Nikki was concentrating more on scrubbing up than what she had to say, Makosi retreated to the sofa and made a point of thanking Preston again for the dinner when he next walked by.
When the singer this time took note of her praise, she smiled and said: "That's good, that's good, we're getting there."