Faulty shoe fit

I purchased a rose gold Superga shoe and had to return it 3 times due to the cut. Finally exchanged the shoe for a size 36 and wore it for the first time on Monday, 29 February. 2 hours after using it, I had to remove it. The left shoe hurt me so badly that it caused my toe to bleed. I called the Rosebank branch that same afternoon and After explaining the problem I was assured me that the shoe can be returned if in a salable condition. I took the shoe to Rosebank on Friday and the salesman, Kenny says that the shoe cannot be returned cause it has been worn. I tried explaining that the problem with the shoe was only found after wearing it as the shoe was fine when I put it on in the morning. He refused to understand this and said that there is nothing that can be done. We then asked to speak to the area manager to whom he was keep phoning and he said that we must send an email. After insisting on speaking to the area manager he then goes into the storeroom for a very long period before returning and handing us the phone. The area manager then eventually says that we must leave the shoe at the shop and they will get back to us in a week. Absolutely terrible service!!!!