Please help

I bought a Samsung 9kg topload WA9OH4200SW from Game on 28 April. I fell and injured myself that day, so I only ended up using this machine on 16 September. I then discovered that it does not have a tumbling action, it only agitates left and right, and so the clothes doesn't wash clean. This model is a 'dud'. I went back to Game on 23 September and they said to bring back the machine and I will get a credit. Yesterday - 26 September - when I took the machine back however, they had a different story. They say that Samsung won't give a credit but that they will send a technician to repair the machine! The machine is not broken, it doesn't have the tumbling action, so I don't want it. That specific model is a 'dud', for missing that feature. I want to buy another machine that will properly clean my washing. Please, can someone help me to achieve this. I cannot wast this much money on a 'dud' when I was not informed upfront that this machine lacks important features. Game and SAMSUNG must sort this out between themselves and refund me or give me a credit. This is unacceptable.