Store refused to acept returns of a faulty zip of the pants purchased on 22/09/2017 & returned on 24/09/17 claiming its wear and tear

I bought black leather pants on Friday 22 September 2017 from Zara in Menlyn. I wanted to wear the pants on Friday evening at a ****tail party. The pants zipped up but when I tried to tuck in the shirt the zip of the pants opened up in the middle leaving me stuck inside the buttoned up zip with the middle completely opened. I used force to open the stuck part of the zip and opted for another pair of pants. I took back the pants on Sunday the 24th of September. The store refused to exchange the pants claiming it is wear and tear. I understand the concept of wear and tear, which happens after usage of an item for sometime, unless someone wore the pants inside the store before my purchase then wear and tear argument can stand but as for me i did not use it over time for the wear and tear argument to stand. I have not gone outside the house with the pants I am very much aggrieved with the outcome that Zara South Africa's customer service cannot assist me I feel it is ****************. Please help expose the unjust customer service from Zara clothing store.