Fail to deliver repair motor vehicle

My car made a strange sound and someone referred us the Jarred. He gave our car back but with a different sound. We took the car back to him and our car is total broken. Every time he would strip the car and put the parts back but with no success, and everytime he would say just an hour then my car would be fix. It went on like this for a week. I gave him a time frame but he could not deliver. The Friday night i went to him and said to him if he cant fix my car he must just say so. He ask to give him until the next morning 10 o'clock. My husband went to him and same story. I ask him not to deliberate sabotage my car because we have small kids and if something happens to them , than he said he also have small kids. The Saturday i drew up a contract and he said that we must take the car to Tavcor and he will pay for the repairs . this is over a month that we waiting for him to give Tavcor the go ahead . He spoke to them and said that he will pay for repairs because it is his fault the car is not running . When we took our car to him it was still running but he had to phone a tow truck to take the car to Tavcor when he was done with it. He signed the contract with two witnesses.