No stock for promotion

I wasn't happy about pick n pay Epsom Down, on Friday 26 June 2015, i say specials on their pamphlet and decided to go and buy there since its close to work, but when i got to the store and went to the shelves as i was looking for Mac washing powder, the shelves where clean like there was never even one bag of it, even no pricing on it, and i asked the teller and the promo and said i should ask the store manager (he was an Indian guy) he told me they are out of stock but how? since you are advertising something that you don't have in store, he told me their distribution centre never delivered enough stock... My question is why you advertise something and tell me you don't have stock... because after that i Cambridge Randburg and there was a lot of stock for Mac washing powder, i even felt i just waisted my time by going to Pick and pay... it just a waste of time going there will never go again...