damaged Goods Not accepted back

i bought my daughter a pare on Nike Air Max sneakers. within 2 moths of purchase the stitches on the takie were torn. we took it back to the shop and we were advised by (Mathapelo) that they will take it back to the supplier, we asked for the copy of the receipt as we have lost ours, they could not find it on their system. we went to the bank to and made a copy of the bank statement as we have by a card, still after that there is no receipt. i then asked how are they going to take the shoe to the supplier they said they will use someone else receipt. 2 weeks went buy and we did not get any feed back from the store. i then called the head office and explained the situation to them they told me that they do not take their staff to the supplier but the regional manager ( Sethu) is the one that assesses the takies. i was told to send them back to the store for the Regional manager to assess it and i did so. the manager called my husband and asked if the child has a scooter. may husband said no and then they told us that they cant take it back because its the Kids fault that the stitches are torn. i man how can we buy a R600 shoe and within 2 Months through it in the bin :(