How should i file a case against an auto mechanic? What papers or argument should i put in front of the judge? Car is Nissan altima 06 with 50k Miles

My car broke down and i took it to a auto mechanic. He called after 2 days and said timing chain is gone and cost of fixing it will be $1300.I said go ahead and do it.I called him after 15 days to check on work and he said he is still waiting on parts. He called me back after a week and said my car is under warranty so why don''t i take it to dealership. I said, I will do that. Then he said he needs $900 because he already ordered the parts and the labor to put the engine back in. I told him rather towing it to dealership, which is 150 miles you go ahead and fix it. I didnt hear from him for a week and almost after a month i called back and he said radiator is gone too. I asked him to fix that too. He called after 4 days and said the whole engine is gone and car cant be fixed and take it to dealership. He charged me $1600 for labor and parts. Nissan told me He made fool out of me. Nissan said if engine was gone, he would have known while putting timing chain.