Truworths-quality issues and refusal for refund

My son required a pair of black shoes for an interview abroad. We decided to go to Truworths in Fourways Mall, as we thought that they sold quality shoes. On arriving home, he tried the shoes on with his suite. It must be noted that he wears custom insteps and therefore always inserts the insteps before putting on any shoe. He then noticed that the quality of the shoe was poor and was concerned that it would begin to fall apart shortly after his arrival abroad. The pair of shoes was returned to Truworths. Being an upmarket store, we thought that the refund would be done without any issue but to our surprise we were informed that this cannot be done as he had worn the shoe outside of the store. Now from a hygiene perspective, the shoe was not compromised because of the use of insteps. We were then informed that the matter will have to be taken up with senior management. I received a call from Truworths in which I was informed that the area manager advised the store that , 'the shoe cannot be returned because it was worn outside of the store." It has taken me a while to recover from a heart condition and to process this ridiculous feedback. I will never purchase anything ever again from Truworths - selling inferior quality at high prices with no option of returns... I am a pensioner with very limited income. It took several months to save up for the shoes. I feel that because of my age, I am being totally taken advantage of by a big corporate. I have no need for the shoes. My son has already departed from South Africa. We had to buy shoes elsewhere for his interview. I just want my refund. The shoes are still in Truworths possession.