Refusal to accept my 5 cent coin

Shopped at Spar at Retail Crossing yesterday (04/01/2016) and my total was R320.30. I paid the 30 cents with a 20 cent coin and two 5 cent coins and the cashier refused to accept my 5 cent coins. She could not provide a suitable explanation for this and insisted that they could not accept these, so I asked to speak with the manager, whom she blatantly refused to call in spite of my insistence to speak with them. After seeing that I would not budge, she took out a 10 cent coin from her pocket, gave me back my 5 cent coins and proceeded to assist the next customer. Her bad attitude and pathetic treatment of me as a customer will ensure that I will never return to that store. And for Spar's information, a 5 cent coin is an acceptable form of payment and refusal of acceptance can see you reported to the SA Reserve Bank.