My Nissan Xtrail '18 has factory fault

My newly purchased Nissan Xtrail 2018 model has factory fault. It had engine light on two months after purchase. I took it in to Nissan dealership about three times without resolution. The technician said its factory fault,and certain numbers dont match parts (was too technical for me to grasp).he said i had to take it back and sales rep confirmed i would get courtesy car in the meantime. This morning went to nissan to take it back andwas caused so much drama.the manager said to leave my car and wouldnt give me courtesy car.he said to call nissan directly as this isnt his problem. I am frastrated if i keep the car with fault and somthing happens to me on the road but if i leave it i dont have a car to commute to work .this has been an inconvunience to me and my family and i hope Nissan SA can assist.