Checkers Woodlands wrong pricing

I went to Checkers and found peeled red onions in a basket with a big shelf talker saying R 19.99, but when I got to the till points it scanned as R 29.99. I went to the shelf and then got told the price is for brown onions and not red. Called the manager, but he just stood with his hands in his pockets and said thanks for informing him and did not really do much. Really disappointed.