Flies on food

I (used to) shop at Pick n Pay Nkomo Village in Atteridgeville. On four occasions, two of which I spoke to Store Managers, I complained about the green flies, especially on the baked goods. After my second complaint, some of the breads were covered, but others, like the panini station and Coney rolls were left uncovered. About a week ago when I was there, I did inform the Manager that I was going to send a review. What surprises me is that I also buy at Pick n Pay Village Mall, Hartebees, and I have note seen any flies there, even though they basically sell the same stuff.