Bad Customer Service

I bought a pair of shoes at Solo Shoes in Eastrand mall Ekurhuleni , then I wore them indoors and I realized I can't walk in them as they were too tight ,I then decided to take them back to the store in their original package and the slip for exchange, they refused claiming that I have worn them. I decided to leave the shoes in store, I emailed Customer Care(Solo Shoes Head Office) hoping they will resolve this matter but I didn't get any response. Please assist me in getting exchange or refund, I cant lose my R500 just like that.