False advertising.

I bought a gown at Ackermans west street durban it was on the 50% off rail. I get to the till l am charged the normal price. When l ask the cashier, she says only items with a red sticker are on sale. So why were only items facing the door had the red sticker and all others on that rack had no sticker? She says because “we” customers leave items anywhere. Is ackermans telling me that their rails were filled by unknowing customers and nobody bothered to clear that? And why are we all choosing the same items to leave on this 50% off rail? Yet l got the same item at Ackermans workshop for less the price l am paying now.