Poor customer service

I am very heart-broken with the service I have received from NISSAN CMH Durban. I bought Nissan XTrail 5 years ago. I've been servicing my car with the same dealership, I have literally done everything pertaining the car with them. I recently had a problem with the car, Jerking when I am driving or accelerating. I had no choice but to send it to them since there is only one Nissan dealership around my area. I left my car on Thursday ( 06/02/2020) with them. I was told that they need to diagnose the car to find out what is wrong with the car, I then asked them if I will get a Loan-car and they said I will they just need to confirm with Nissan if its under warranty. I then phoned their head office and spoke with FIONA STEYN, she told me the same thing that they will book the curtesy car once they know whats wrong with the car. I phoned FIONA today and she told me that they are still inspecting the car. I then phoned the dealership to find out whats holding them, LESLEY(THE SERVICE CONSULTANT) told me there is something with the ENGEN, they need to send it to NISSAN so they can give them a go ahead. What I don't understand it that's the two department have different stories and according to the dealership they have already diagnosed the car. They are making fool of me. All I am asking for is a curtesy since my car is still under WARRANTY, I work with customers, that's the reason I bought the car in the first place. I am not even able to do my work, I am loosing income. my case number is ***4.