No refund on item sold falsely and does not do what it was advertised as

I ordered a carpet shampoo machine because it advertised that it sprayed the liquid onto the carpet and then scrubbed the shampooed area and had a suction to pull up the moisture. Well neither work and the scrubbing brush does NOT rotate and scrub, you have to push and pull the machine to scrub. Better off doing the scrubbing by hand. They refused to take the machine back and refund me R3600. The advert was a total lie. They refused as I had opened the box and had tried the machine. How else would I find out that it was a total lie that they sold me. Goodness knows what the big heavy motor does as everything is manual??? Never again.