advertising promotions false

Terrible service, so pick n pay is having a special on the nestle chocolates, you can purchase 3 x chocolates at R 20.00. We normally purchase this on our office breaks, yesterday a college selected the white nestle 4 finger kit kat and some other variants, today we did go to get the special as well only to be told at the till that the special is only for certain names in the nestle brand my argument then was, why does the promotion state and show different variants of the products if it only applies to certain items, is that not false advertising, then i stated that a college purchased the exact same chocolate yesterday, i was the told i a rude manner that the bar codes are different, i work for a company that makes bar codes, its obvious but lets not deviate from the topic at hand, is there a difference between brown chocolate and white chocolate that its not included in the promotion as its to expensive to promote, lets not make this into a race thing but more into, poor service, bad customer support and information and most false advertising, if its a promotion state the exact items specifically on promotion, a waste of lunch time, we had to go to the cigarette counter to get a refund