Bad attitude of call centre agent because of R85

Today I received a call from a very cheeky call centre agent from Head Office, treating me like a ******** because I paid R400 and not R485 last month on my account. I am flabbergasted that you at the Foschini Group can make such a fuss over R85. This lady also wanted to know if I am going to pay it today or tomorrow. REALLY!? I asked her to confirm if I have ever not paid my account before the 1st and she confirmed that I have a positive track record in this regard. I apologise that I lost my temper during the phone call, but being a business owner myself, I will never use such an antagonistic tone with my clients, even though they sometimes owe me thousands of Rands. If this is going to affect my credit record BY ANY MEANS, I will go to the newspapers and any other customer protection entity there is.