Total Sports Cresta not honoring marked price of a product.

Went to buy running socks at Total Sports Cresta. Price on the item was R75 and it was rung up for R85. I mentioned to them that the price shown should be the price you pay. The person who said he was the manager, but would not give his name, said this is not the case and would not accept the marked R75 price. Shops should honor the shown price of their products, otherwise what's the point? So for R10 Total Sports Cresta lost a client.