Frontline Staff member refuses to supply what I order

As I do so often, I requested 5 x Streetwise 1's with Mash, Gravy & Loaf and I always specifically ask for Side Breast Pieces. This time I was told I can only get 2 Side Breasts. I asked if they have run out. I was told "No, nut you can't take all Side Breast." What a cheek, I pay for what I order. To top it up, I called the KFC Customer Care Line, only to be told in effect, if they supp**** me 5 Side Breast there might not be enough for the next customer. Just as cheeky as at the branch.