Bad bad customer service

Hi.. I'm so unhappy after Saturday's incident at pep stores denlynmall in pretori, on the 6/7/2019 at about 11h40 I went to pep stores to change the clothes my child's grandmother bought over school holiday for a bigger size as those were to small.. As I get to the door a lady with the name Betty assisted me and when I told her the slip is misplaced but the tags are still on, she refused to help me. So I asked for the manager.. to find out he/she is not there but the person who is 2nd in charge will help me.. when Zabe came she did not even look at me and told Betty that I must call complaints department, I then asked her why she does not explain to me she told me that Betty will explain.. Betty gave me the nr *** to call and the lady I spoke to asked me why they couldn't help me when the goods are still in good condition and she asked to speak to the person in charge, when Betty went to call Zabe again she was told that Zabe went on tea, a Mary/Maria spoke to the lady from customer service and told her the regional manager said that they cant exchange goods with out the slip.. when they gave me the regional managers nr he dropped my calls 3 times.. the people that was supposed to assist me left me there standing like I'm an item in pep, I got so angry and left the store as they made a joke out of me.. talking to each other and looking at me.. I never had such a bad customer service in my life.. they should send them for training.. I'm very very unhappy