exploitation of consumers when selling your products

Last night I purchased a 2 L Coca-Cola product from a shell service centre in Phoenix Durban. The price on the label of the 2 L cold drink indicated that the product is 17 rands. At the tool when scanned I was asked to pay R32 for the 2 L cool drink which is almost double the price of what it’s advertised on the label please can you investigate this as this is exploitation of consumers having to pay double what the actual retail price of the product is