Very bad service received at Pep Store in Lenasia CBD

I purchased shoes for my son yesterday (13th September 2017) which were not the right size, then today I went to do an exchange when I had an encounter with a cashier named Mathapelo Molefe who decided to litteraly pick an urguement with me over my proof of purchase. I mean really, she raised her voice on me and urged with me because I asked her why would she just keep my original slip without even asking me if I would or might need to use it because it had more than 10 items that I purchased yesterday. It's common sence you can't just take and decide to keep my slip because in your poor in service training you were told to do so because she literely told me that she was never trained to ask and there is no such a thing as reprint of a slip if you purchased something the previous day. On top of it all she asked me to pack my own things saying is it I do it at pick n pay. I mean she doesn't even know me, when did she see me pack my things at pick n pay. I am very disappointed and angry.