Card Facility only swiping R20 and up

I went to postnet in gift acres mall on lynnwood road yesterday and i was told i cannot swipe for less than 20 rand due to the company running at a loss in terms of fees, i spoke to the manager he didnt really seem to care that he is inconveniencing me, as far as i know a business with swiping capability should never inconvenience a client and tell them they refuse to swipe for less than 20 rand its the same as if i ask said business to pay my bank charges it goes against my consumer rights, the manager also gave me a number of the store Owner Osman *** but this number is answered by a female and the call gets dropped in my ear so unable to communicate this is pathetic