Disappointing customer service

Today we went to 2 different PEP stores in Pretoria North and spent more than R300 at each store buying uniform and other stationery things for our son. We paid using our FNB card in both stores. We then learned later at night that we actually qualified to buy that R0.99 cents pair of shoes. None of this stores actually informed or mentioned this to us. I'm not sure if they are supposed to keep quite about it or promote and encourage it to their customers. What's surprising is that we were buying school uniform and they could've easily remembered to mention this school shoes promotion to us. We are so disappointed!!