R600 got for 2 week shoes

I want to complaint about the service that I have received from total sport menlyn, I bought sneakers from total sport menlyn on the week of 16 june 2019, for my sons and after a week they were already torn due to quality, I paid R700 for a pair and took them back to the storeto complain about the quality of the shoe as they were bought about a 2 week ago and already they are damaged and I believe it could be a factory fault and when I got to the store I was told to bring the box and I explain that I did not keep the box because my intention was not to return them and I thought I bought quality from a most popular shop, only to be disappointed that they cannot help me without a box, but this is a complaint abount the quality, 2 weeks R600 gone as if I bought from the street of jozi, please help me out, I cannot take the fact that if I don't have a box I cannt be helped like really something can be done.