unsatisfactory shoe quality and service

Good day

I would like to complain about a shoe I bought at Zara Sandton on Saturday. I wore the shoe on Sunday afternoon and the heels are now both worn out. I took the shoes back today to Gateway as I reside in Durban but they refused to exchange them for me. The manager said its damaged and that's exactly the reason why I want to exchange it. She then continued to ask me where I wore them too, which left me confused as I didn't know there are certain areas where the Zara shoes can be worn, however I did advise that I don't take public transport, I left my house and to the parking of a restaurant and into the restaurant, which I'm thinking the damage was from the parking into the restaurant. I also wore them on Tuesday to work which is a tiled and carpeted environment. I did advise I have pictures of where I wore the shoes to. She then said that they cant take the shoes as they have to resell the "damaged" shoes and they cant run at a loss. So my question is, who is the one that should run at a loss, me? I have numerous shoes bought from Zara that are over 3years and still have their heels intact despite of the extra sets of heels that Zara provides as I thinking they are aware that they have a problem with their heels. Unfortunately this pair didn't come with an extra pair. I left the shoes at the store because they said they will consult their customer service department with a lot of attitude and sarcasm which made me not trust the feedback I will get in 24-48hours that they promised.

I have my receipt as well as where I was the day I wore the shoes and pictures of other shoes from Zara that are still in good condition despite where I wore them to.

Regards, Sindi