Spitz Jabulani Mall pathetic warranty policy

I bought a Kurt Geiger shoe at Spitz Jabulani Mall in Soweto and just a couple of months later the shoe was torn. Last Saturday i went back to the same shop i bought the shoe from to return it because it is still within the warranty period. The manager was not in the shop that particular day and some *********** woman named Lindiwe ( assistant manager) refused to exchange the shoe because i put a sole. Common sense is that when you buy a formal shoe, for the shoe not to be slippery especially when you walk on tiles you put a sole and it also helps to pro-long the life span of the shoe. So i fail to understand why this could void the warranty. It also makes me very irate that i had to spend two hours in the shop because of this *********** Lindiwe trying to communicate with Spitz head office but at the end of the day failed to resolve my predicament. I intend to take this matter further.