Items missing from my order

I frequently visit Chicken Licken, just off Rivonia Road. At some point, last year I ordered a lunch meal and no cool drink was added to the meal, even though I paid for it. It was just too much admin to report the matter so I just let it slide. However, about 2 weeks ago I visited the store again and ordered a meal for my family... much to my disappointment, they gave me less wings in my order. Is this a cost cutting/ money saving technique or was it a genuine error? What are the checks and balances? Once is forgivable, but a 2nd time is unacceptable!