Bad service

I have never been so disrespected by the manager of pick n pay Diepkloof Square by the name of Zandi Nzuza the we advertising a special of getting 3 packets of chips either simba,lays or nick naks however the nick naks where not available i asked her that what must i do hence the advert its there but you dont have stock instead of her telling me lets mayb take 2 packs of the same brand to replace for the nick naks she told me that the is nothing she can do because some people where on strike, so am asking myself why should their affairs be my problem but to cut the long story short she refused to sell me the chips on that special price and she told me to buy those chips and come back to fetch them at a later stage or leave them what a disgrace of a service yet i spend lots of cash in that shop.