No Refund at the store

Hi,I bought a dress last week for my sister,but its too big.I then visited Potchstroom mooi river for return on the 20th November for refund.The ladies told me the don't have enough cash on the tills i must come late or tomorrow. The following day i went again for refund i was given same story, they only have 400 rand available in the till,I must come on black Friday, people will be buying, so they can refund me.This is disappointing service,firstly its petrol to get to the mall and secondly how can the shop return customers back. something needs to be done we cannot accept such treatment and this will my last time buying from the store