Bad service and attitude

I went to Cambridge food Bloed this morning to buy bread when I arrive at the Cashier Denia Mohlongo assisted me i paid with a R2-00 that had black marks on it of which i got it at Cambridge on Monday she refused to help me she told me that i must give a proper R2-00 what is a proper R2-00 because i got it from Cambridge why did they give it to me to start with if they have a problem.Cambridge is not her store she is an employee there and her attitude stinks she cannot tell me that if i will agree if a person gives a R2-00 and she is not the one who gave that R2-00 on Monday is it how Cambridge train their staff to have an attitude towards customers and answer them the way they want I'm a paying customer i didn't go there to ask for loan and be treated like that i wanted to pay for a simple bread with the same money that was give to me by her colleague