Food and Bad service

I recently complained about being sold stale nuggets of which a agent called and said the store manager will be in contact with me soon. Only to receive a call from the manager apologizing the mishap happened because she was off duty. I asked what is the way forward I was told you go and try and see if the same problem is repeated. Which I go at a different franchise. Guess what now the manager is the rude one not willing to assist walking away saying that she has a lot more serious issues to deal with. I luckily bump into another manager and he says he will deal with the staff. I'm like it's fine il take it to social media he says makes no difference because whatever complaint I make he will get the complaint and he will tell me the very same thing. I mean the audacity. What's the point of complaining if they know nothing will happen to them. I now understand why people would rather buy a R100 burger at Rocco Mommas than at Mac Dees