Disappointed

Hello, I went to Shoprite store Charlesville to exchange a stove that I bought April this year. The manager said that the store is not the one from store, I am returning the old stove,said that it was rusty and old. I told him that I use the stove every day, and it's not bad as he said. The guy didn't listen and that stove is two months old. Im really disappointed in Shoprite, and the way he handled the situation was not professional. I also don't understand why they have the exchange warranty, and refuse to do the exchange.