[California] and [Iowa] - Maybe need legal action?

So, long story short: my wife and I live in Iowa, and until May of this year she worked remotely for an employer based out of California for just under two years as a regular full-time salaried employee. The division she was working for folded up at that time, so she was let go along with the rest of her team.

We filed her unemployment right away, in Iowa, which was rejected, saying they had no record of her wages. So, we filed in California, which was rejected for the same reason. We filed an appeal in CA, and the reviewer affirmed the rejection, and told us we had to apply in Iowa. We went last week to the Iowa UI office and worked with a woman there who said she searched both IA and CA's system, and neither of them have any record of any wages associated with my wife's SSN.

We contacted the HR office of the company she worked for, and they said we would need to call the payroll company (TriNet) and verify her SSN was correct in their system. We did that, the SSN is correct as far as TriNet is concerned, which means it's correct on her paystubs, and it is correct on her W2s as well. Since then, the HR department has gone dark on us - we call, it goes to voicemail, we send emails, they don't get replied to.

My guess is that the HR department failed to report our wages to the appropriate state and is now hoping we just leave them alone. Beyond just haranguing them over phone and emails, what else can we do here? Is this legally actionable? We've never been in this situation before so we're not sure what to do if we can get them to work with us on the problem.

Thanks!