Refusal to sell me at the marked price!!!

I just came from Shoprite Liquor Langa, Cape Town. I saw a price tag next to the Hennessy Shelf showing a price of R379 for a 750ml bottle. As I went to stand in the queue to buy it, the lady at the counter asked a customer who was in the front of the queue to quickly remove the price tag, and when I got to her I asked her to give me the R379 Hennessy bottle as they keep cognac bottles by the counter. She informed me that there is no Hennessy for R379, and that the price has been removed from the shelf. So, I said by law she was obliged to sell me the bottle at that price which was reflected and she blatantly refused and I left it there. I find this very ridiculous and utterly unacceptable. I want thag Hennessy VS at the price which was reflected when I walked in and I cant be held responsible for Shoprite staff incompetence!!!