Poor customer service

I had a terrible experience in McDonalds Brookside mall in PMB(KZN). I ordered a hot chocolate and when I got to the counter to pay I was than informed that it was out of stock and they offered me a capeccino instead. The laddies were dragging and busy talking their own stories. After waiting for more than 10 minutes, I queried why it was taking so long, the lady responded and said they are not machines they work according to their own pace, she was literally arguing with me in front of their manager. PLEASE RETRAIN YOUR STAFF ON CUSTOMER SERVICE, THIS IS UNACCEPTABLE.