Very bad service from the call center agent and supervisor or manager

I made an online order and was charged an extra R60 for delivery wheres I have an account and delivery for items more than R500 delivery is free. I then called the call center and queried,I was met by a very uninterested person on the other hand who did not have an idea of what she was doing, she told me that the supervisor would call me back then, it was around 12, up until 4,no one bothered to call, l called them again for 4 times and was then called back by a manager or supervisor by the name Lee, he does not speak clearly for starters, and has no customer care at all,he said that i was at fault that the system did not recognize that i have an account hence I was charged for delivery. I am not going to forget this one , not anytime soon!