Car service city sucks!

My car was serviced and within 2 months had broken down. The damage is something that car service city should have picked up but didn’t, like the previous company had done. On enquiry they claimed the car had a different fault which wasn’t their responsibility, only to find out what they said wasn’t the fault was actually what made the car break down (meaning they didn’t even inspect the car or what’s damaged). I had to go somewhere else where they confirmed what was damaged is something that should’ve been picked up during a major service, meaning car service city took short cuts and didn’t pick up that a part had to be replaced. The part has now affected my engine, and car service city says it’s not their problem. They didn’t even asses/diagnose my car after I brought it back and just told me the problem is not what I think it is (knowing very well if it was, they would be liable). Car service city is trying by all means to avoid liability after not performing their major service properly, and would rather point out a fault that doesn’t exist. When sending email query to their head office customer relations, it takes me back to the branch staff where I took the car and those people refuse to take responsibility. Meaning head office doesn’t see the need to help resolve this matter. Their head technician/ mechanic Chris at Ormonde branch just tells you the problem from the top of his head without diagnosis and when I asked what if he’s wrong, he told me he’s done this for 26 years! I’m dissatisfied because I trusted this company with my car. Now they can’t even do a proper diagnosis because they want to avoid liability. Chris just brushes you off so you can go away. Don’t ever use them, they don’t care about you as a customer!