How to Deal with Stealership That Doesn't Attempt to Fix My Car

My question involves a consumer law issue in the State of: California

I’m having an issue where my car pops out of gear when going downhill in 1st. Google tells me it’s definitely the transmission synchros, which is what I told the service rep. It's still under warranty.

I took it to the dealership for service and they said they would try to replicate the issue. When I mentioned that there’s no place in Santa Monica with a hill steep enough to do that, he said, “they’ll just go into the Palisades.”

When the service rep called me to pickup the car, he said the tech drove it as well as the service manager, but neither could replicate the issue. He said Subaru wouldn’t “throw parts” at a car unless they could verify the issue.

When I reviewed the dashcam footage, one guy drove my car around Santa Monica a bit, but not down any hills in 1st gear. There was no second driver and they never tried to duplicate the issue.

I'm looking for advice on how to approach the dealership to get my car repaired now that I can prove they're blowing me off.

Thanks

How to Deal with Stealership That Doesn't Attempt to Fix My Car