IX35 engine dies after 6yrs

I bought a brand new Hyundai IX35 in December 2012 registered it in January 2013. I have always taken it in for service once a year as I did not travel 15 000km. Last year October was my last free service. This year 2018 October the car just cut off on the road. I had it towed to Hyundai Brackenfell. The are telling me that the engine has died and I must pay them R77 567 to have my car fixed. I am shocked that after driving the car for 6 years I have to buy a new engine without any explanation why it died. If they had told me upfront that this would be the case I would not have bought their car. I still have a Toyota tazz bought in 2001 and the engine never died. I would appreciate if Hellopeter can be of assistance as I feel I am being taken advantage of.