Do not accept R200 without Madiba's face

I withdrawn money from a ATM outside Spar and went inside to buy some items. When I wanted to pay with a R200 I was told they do not accept a R200 note without Madiba's face! I told the cashier that it is is a legal note from the bank, but was still refused. The manager told me it is the owner's instructions and that he can't accept it. I left the Spar without my goods and went to Shoprite just around the corner, bought and paid for my things without any hassles. I phone the Absa branch and according to them, Spar MUST accept the notes. What can anyone do to ensure this doesn't happen anymore, maybe Spar's Head-office can step in and demand this owner withdraw his policy as this is against the law