<human>: Can you condense the text into a few key points?

I took my car to a shop (national chain) because the engine was shaking upon startup. After driving it out of the shop it started shaking again plus overheating. Brought it right back and the mechanic claimed it was a coincidence. I pointed out that they had done a full diagnostic before hand and found no overheating. District manager fixed the "new" problem free of charge and I drove it away.
The next day it started shaking again. 

I called up the district manager and requested to be sent to another location free of charge. This location has been great so far and put me in a free rental.

Two days later I get a call. Turns out the problem this whole time has been a leak that's been flooding the engine. I very easily could have had it lock up on me on the freeway, according to the new shops mechanic.

I requested they fix it for free (original fix was 400, new fix would be 1,400) for time and money lost and their incompetence putting my life and those I was driving around in danger. (I was told it was safe to drive without fixing first and drove it to work and back. )

Claims guy calls me up and says it will be handled in a few days and they would have a decision. Basically the old shop would have to pay the new shop for repairs. It's now been 3 weeks. I keep getting the runaround from customer service and apparently my case has been resigned to someone new recently. I have yet to hear back from anyone in claims. At this point the money they have spent on my rental is substantial enough that they may as well have fixed my car the first day.

What are my options? I live in Los Angeles
<bot>: Car place has had my car going through the claims process to fix one of their locations big mistakes for 3 weeks now and I can't get a hold of anyone. What can I do?