Pipe burst during the freeze in January - insurer is saying I "failed to maintain heat" and denied my claim

My pipes froze and burst during the cold snap we had in late January. I was out of town for a work trip for 4 days - I set the thermostat to 62 before I left, which is what I always do. I came home to water pouring through my kitchen ceiling. The damage estimate from a restoration company is $28,000.

State Farm denied the claim saying I "failed to take reasonable measures to maintain heat in the home." The denial letter cites a policy exclusion for "freezing of plumbing when the dwelling is vacant or unoccupied unless you have used reasonable care to maintain heat in the building." I had it set to 62 degrees. My neighbor has the same policy and he keeps his at 55 when he travels - but his pipes didn't freeze so it didn't come up for him.

What frustrates me is that 62 is objectively warm enough in normal winters. The temperatures dropped to -12 that week, which is extremely unusual for our area. This was genuinely an unusual weather event. I also had someone check on the house during the trip - my sister stopped by on day 3. Does that affect the "unoccupied" language at all?

Has anyone successfully appealed a denial like this? I'm wondering if I should get a public adjuster or go straight to a bad faith attorney.