That’s SOP for a gas and sometimes water companies. They move the meter to reduce their exposure to repairs. Once the meter is moved, the additional piping between the meter and the house is the owner’s responsibility. Even if you prove they moved it, it won’t make a difference unless Kalifornia has different consumer protection rules than other places.
I think you have nailed the core issue. While you can sue you would probably lose and be out legal costs as well. Probably best to suck it up and pay to get it fixed.