Rude manager-complaints no on till slip ***

I was not happy, I waited almost 30 minutes and my order an decided to complain to the staff, they informed me that I can call the number on the bottom of my till slip to speak to the manager and log a complaint. I called the number, *** a lady answered. She was very rude towards me as a customer, she was not friendly, courteous, she insulted me, I asked her what her name was and she said it was Sandra. When telling her that I wish to complain about waiting so long for me order she told me that she was not stupid and she can see me, (from the camera). I got into a argument with her about her customer skills and what it is that I expect from her as a customer of KFC, she informed me that she was also a customer and that I must understand her position. I informed her that if she is not prepared to listen and deal with customer complaints and if she don't want her number on the KFC till slip then she must have it removed, she informed me that she will just do that and disconnected the line. i must say that never in my life was I so insulted as a customer, I informed the manager on duty that I did not even feel like eating the food, this is very disgusting service.