Poor quality shoe and Castelo won't take responsibility

I purchased the shoes during the black Friday sale on the 24 November 2018 at Castelo Sandton City. The shoes in question costed R1450 marked down from the original price of R1850. I bought two pairs and the total spend was R2495. On the 26th December 2018 while at a family function in Durban I realised the shoe was torn. The shoe is made of a clear PVC material. I immediately called the Castelo sandton branch to inform them that the shoe is torn in less than a month after wearing it a few times. The guy on the phone advised that I should bring the shoes to the store for assessment. I advised I am out of town and can only bring the shoes to the store on the 3rd January 2019 on my return. On the 3rd of January 2019 I went to the Castelo sandton branch to return the shoe as advised and the black gentleman who was assisting me advise that the manager is not in and on her return that day they will call me back regarding way forward. While at the store while showing them the shoe another assistant imp**** that I had deliberately torn the shoe. I left the shoes and went home called back in the afternoon if their manager has seen the shoes and was told she hasn't they will call me back in the morning. Please note I had to be the one that follows up and even the next day on the 4th January 2019*I was the one who called them since they did not bother to call. On the phone I was advised the sale assistant who was handling my case is on leave and they can only help me on his return. After insisting that someone should assist with the matter another sales assistant spoke to me and check the purchase details as I return the shoe in the box it was purchased in as well as bank statement. She advised that since I bought the shoe on sale there will be no exchange or refund. I did not accept that a shoes that costs so much can only last a month. She advised their operations manager will call me back. I further lodged a complaint on their Instagram account. Around 1h49 pm on the 4th January 2019 a lady who introduced herself as their operations manager called me she expressed her frustration that I had complained on Instagram and deemed it unnecessary. She further advised that the shoe is one of their best seller and there has never been any complaint. She was insinuating I had torn the shoe on purpose. She advised that it will be sent to their shoe analyst who will be back on the 15 th Jan and there is nothing they can do for me. Her tone was of blame and mentioned that it's wear and tear. How can a shoe that cost so much from an establishment that prides itself in quality have wear and tear in less than a month. To date the shoes are with them and from the tone they are not willing to take responsibility for poor quality of the shoe hence it got torn in a month.