Have 64 plate capture & had engine completely cut ...

Have 64 plate capture & had engine completely cut out on me whilst driving with no warning signs at all! Brought car originally from dealership in the summer 2015 & had full service history with them every year since. Been told I need to pay for a new engine that will cost the same as what the car is worth. Renault refusing to take responsibility. Not acceptable. Please tell me why I should be liable for this cost & what I could have done to prevent my car cutting out on me?