Overcharging and no willingness to help

Today we went to Tops on kingfisher drive.. they have a special of R20 off when u buy 6 pack of 500ml flying fish. At the fridge it's priced at R90 each pack...at the till we get there they say R95.. we paid and went back to ask them to give us at the price that they have at the fridge. The guys was unphased he said , if he gives us at the price that they have on the fridge then we won't get the R20 off each pack..

So is that the terms and conditions that u pay extra to get the R20 off,so actually there's no special here.... I drive from douglasdale passed pnp to go there . I should've just bought there cos there the price u see is the price to pay but not at Tops. Will never go there again