Bad customer service Nike shop , Sandton City

Few days ago the company x mas lunch we recieved Nike Solay Thongs , mine were size 7 ( my size is 5 ). Shoes had the tag , barcode l, only store slip was missing. I went to the Nike shop in Sandton City to see if I can exchange shoes for the right size. Staff in the store refused to even look in to the metter as I could not produce the purchase slip and asked me if I can go to other sports shops to try to exchange NIKE. product. They did not offer to contact Head Office and try to see how can they help. . They just sent me out. This was not the kind of service that was expected from Nike . I did come back and asked them to contact Nike RSA and get back to me the following day. When asked to scan the pair of shoes to see if they appear on their system , they did scan and told me that it scans " sort of ". This was the wost service that I experienced in a very long time