No respect for the law

I went to purchase some clothing for my nephew and there were garments with yellow sticker pricing so i took a few of those and a few normal priced ones. Then one t-shirt was priced R40.00 on the sticker but at the till it cost me R50.00. So i went back to the tills (before leaving the store) and i showed them. then they said it has now been marked up and that they will refund me. As they took the t-shirt away i was ****ed off because i spend my time (non refundable) walking around the store and selecting items only for them to tell me that if i wanted that t-shirt i have to pay the R50.00. I think the consumer protection act requires them to provide me the garment at the advertised price. I didn't know that PQ is above the law.