Black Friday

Went to Pick n Pay Brits to get Ariel 3kg washing powder, and Jacobs coffee. I was there at 8 when they opened the store only to find that the shelves were empty. I was told that we can take 2kg and 1 kg, to our disappointment, 1kg was also out of stock. Grace asked for my number and promised to call me as soon as the stock arrive (according to her it was on the way because someone already went to pick up some stock earlier that morning),however, I went back at 11:00 and her answer was that they cant find stock anywhere. How can any shop advertise specials, but have no stock...WHY???