Food was placed in a used, oil soiled Dirty Bag

I went to the Drive-thru at KFC Brixton. Firstly they didnt have their advertised PS Crusher which my kids desperately wanted but opted for Oreo crusher . Please my order and went around to next window - paid and then to collect food at the last window. The lady at the window gave my food in a frumpled, oiled dirty brown paper bag. I asked for a new bag and then the other lady said thats how it comes. I got out of my car and said she must compare another bag and the one my food was in. Obvious difference. i insisted on a new bag and finally they gave me one. Then the Crushers - they were half empty and hollowed out. Refer to pic