Dissatisfied customer

I'm very disappointed I am loyal checkers customer, I was in checkers Mayville today, for the awesome specials that was advertised, to my dissatisfaction and dismay I found that the spesial of buy any 3 kellogs or coco pops 350g / 500g was not processed at the tills, i found that i have been charged full price,and for me to drive back to checkers is again extra fuel cost and time for me as a customer , I need to asked how many price and discounts is not being processed when we as customer is paying and buying goods ?????