Damaged shoes

I bought my daughters shoes on the 19 of September 2015 from Woolworths Irene mall. She wore the shoes on the 20th Sunday to church.I saw them on the same day late afternoon that they were torn. I had to wait for next Saturday that was on the 26 to return them to Woolworths because during the week I was at work. When we arrived at Woolworths Lebo the teller agreed to take them back, she said we can go and check if we will be interested in another pair of shoes,yes indeed we got another pair. We took the shoes to the counter to go and pay the difference because it was a different pair of shoes. Sam the manager refused to take them back and insulted me in front of his staff and other customers. Really I am not happy with Sam's behaviour and the service received at Woolworths Irene mall. Please help.