Bad customer service

Good day. Apologies for only sending my review today. My son purchased a pair of Nike Air Force from the Promenade Mitchell's Plain store on Monday 4 November and then discovered the following day that the one shoe is bigger than the other although both display the same size. My mother then went to the store last Thursday to do an exchange but to her surprise and mine, the service was disgusting, after spending R1500. When she entered the store nobody offered assistance so she asked to see the manager. A shop assistant said she'll take to the shoes to the manager but he wasnt available so the store supervisor assisted my mom. He assessed the problem and could clearly see the difference in size but refused to do an exchange. He said the exchange will interfere with his stock take and said that the customer isn't always right. My mom tried explaining that the shoes cannot be worn due to the difference in size but he refused to hear her out. The shop assistant on duty also noticed the problem but she couldn't to the exchange cause the supervisor wouldn't authorise the exchange. We then contacted the head office and received the go ahead to return to the store for the exchange. My son and his dad went back on Sat, spoke to the supervisor again, explained that the head office authorised the exchange but once again Ayabulela( the supervisor) wouldn't do the exchange. My son gave him the name of the person at head office and her number and thought he would contact her but he wasn't interested. I even called Ayabulela myself to explain the situation but his attitude towards me as the customer was totally unprofessional and unacceptable.