False advertising

they had the Jacobs coffee marked R74.99 on the shelf (I have a photo) but at the till point it scanned R114.99.<br> when I approached a senior sales person she said I took the wrong one but according to the pricing on the shelf I indeed took what was advertised.<br> she refused to give me the item at the advertised price so I opted for a refund.<br> I have a pics to verify my complaint