Engen Conrad: False Advertising

Before midnight, on Saturday the 30th of April, I bought items which were advertised as being on special at Engen Conrad. I bought the 2 for R50 Magnum special, and the 2 for R23 Fruitree juice special. When my orders were rung up at the till, the discounts didn't come through as advertised. I asked the cashier why this was, and she told me that the till was set forward to reflect the false date of 1 May 2022, hence the specials didn't go through as advertised. She also mentioned that if she manually app**** the specials, then the amount would be deducted from her salary. This is foul play on the part of Engen Conrad management, and shouldn't be allowed as it infringes on my consumer rights. I am disappointed, and would appreciate that I am reimbursed the amount owed to me as I bought the specials within the correct time, as advertised.