Renault Dealership, not giving assistance on broken engine

I bought a Renault Sandero from a very reputable dealership in Roodepoort. They went through all the necessary steps to ensure that I have a beautiful car, trustworthy. Never had an engine leak, oil leak. Took my car for a service. Within a week my engine was destroyed. A Renault part break and a pulley belt came loose and damaged the engine. My problem currently is that the part that broke caused a lot of money's damage. Renault said they will fix the one section with the part that broke, but know I have to replace the engine R50 000. I have spoken to many people, and they also feel that if a Renault part broke and caused so much damage. It should not be for the customer to pay. I have been battling with the dealership, communicated with Motorite, the ombudsman, Renault customer care, but no one is willing to stand up and even explain to me what and why things are happening. it is just money money money. Is there any other people who had gone through something similar? I just cannot believe that I have to pay for something that Renault's parts caused. And we have to take the liability. I never had any issues until the service. And suddenly now I am going to be in debt which I do not know how I am going to pay back. I was a great Renault fan, but I do not know anymore