Pressure gun machine Makro Polokwane

Hello Peter. I bought a pressure machine for washing cars at Makro Polokwane for R1400. The machine only worked for 2 months and when I took it back I was told the cylinder head is faulty and I need to pay up R1200 for them to repair the machine. How is it possible that I must pay for repairs while the machine has warrant and only worked for 2 months?? I am really not happy with their service. Please help me with the issue so we can resloved it. Thank you