Bad customer service

I used to love and enjoy Nandos until this one time my 2 colleagues and I decided to have Nandos quarter chicken special for lunch and we all had breasts the hot meal, which is what we eat all the time, shortly after we all had tummy ache from which one of us vomited. Tried to take it up with management but they failed to even apologize or try to invistigate as to what could have been the cause that's just how much they value their customers.I called to enquire as to what measures are being taken since they failed to get back to us like they said they would,they said they will get back to us which hasn't happened when trying to reach their customer service we were told that East Rand Mall has to first escalate the complaint(which they said they already did) until such is done there is nothing that they can do for us.