Disgusted,embarrased and humiliated

Hi, I went to Pep in Goldman on Saturday afternoon to do an exchange as my item was too small. The gentleman assisting me was so rude, he took my item and put it in the parcel cubicle,gave me a number and walked away. I stood there not knowing what to do next, one of the other employers "Thabiso" came and assisted me, he apologized for his colleagues behavior and explained how the exchange works, i then asked him how much should the exchanged item be worth. He advised me it didn't matter what price it was and that i could add extra items which i assumed was courtesy due to the previous employee having bad client service. I then proceeded to get my exchange item and as the "extra" i took 2 pairs of sandals and a t-shirt, as i got the the que i confirmed with "Thabiso" that my exchange item cost R80 and that i had taken three extra items, he confirmed and said it was all good the ladies at the till would sort it out for me, I was so impressed with this. I got to the cashier and advised im here for an exchange and also the extra items that was given as a result of bad customer service. The cashier advised that is not the way things are done and then the manager came and also advised the same, i then told her that one of the employees advised me on this and they both disagreed, i asked if they could call him and the manager looked at me like i was a retard and and ignored me, i asked three times to ask the employee, she screamed for him across the room with a full store,i was so embarrassed, she then told the lady to help with the exchange and not to worry about the extras, she spoke to "thabiso" on the side and never cam back to where i was, i continued with the exchange and then the manager shouted and said they dont have my exact item there and made me pay an extra amount on the exchange, I was so humiliated and embarrassed, the manager is a complete asshole that doesn't know how to address clients, i did not get an apology or anything, i stormed out of the store with so much anger. I need this to be rectified, I love buying at pep but this behavior makes me hate pep in general..I am looking forward to your soonest response on how you will be handling this matter.thank you in advance. Abasha Vanrooyen