Assurant didn't cover the labor? I thought they covered all repairs. 30 days does seem a bit on the low side of coverage. Personally, I think they should make good on their repair. You can just replace parts on a whim saying yep this may be what is leaking unless it's a Frigidaire top mount fridge, then you know it's an evap/heat exchanger leak
We always had a 90 day warranty at Sears. There is no way to replace the entire sealed system because some of it is built into the walls. He should have installed a UV drier to verify no leaks, and hopefully he did when he made this recent repair. I don't even understand why companies even touch sealed systems if they aren't going to do it right. Most smaller leaks will take time to leak out and 30 days is not a sufficient warranty on a repair like that. I'm sure California the state of many laws has something to protect you over something like this, but I don't know.