Unpaid Claim Issues

I am going to try to make this as tl;dr as possible but it’s a mess going back 2+ years.

I am a mental health provider in Oregon and billed several sessions in 2023 to the client’s insurance. The claims kept getting denied because they were being processed under the wrong Tax ID. I kept calling to get them re-processed, they would get re-processed and the claim would be paid under the correct ID. In January 2024 I received requests for repayment of those funds, because they still had me in the system incorrectly.
After many back and forth emails, I was told that the system had been corrected, no recoupments would be taken, and the payments I had already received would be corrected to having been paid under the correct Tax ID.
Auto-recoupments were then taken from sessions billed to that insurance in 2024. I emailed requesting clarification and was told that I had been double paid. Only, I was never double paid, I only received one payment for each of the 2023 sessions.
The tl;dr again after many messages is that it appears that in their system a payment was logged in April 2024. This would have been for over $1,000. I can see the payment in their system, but it has no associated check or ACH #. I never received it. No one can find any evidence that an actual check was issued nor that one was cashed.
I submitted a grievance to the state Department of Consumer and Business Services because the insurance is now taking money from me that they never paid me. And this whole thing has been insane with how poorly it’s been managed.
I received a letter from the DCBS today stating that the insurance company told them the issue has been resolved. But it hasn’t, and I have email documentation from a month ago where I emailed the insurance and asked if it was resolved, was told they were looking into it, and never received follow-up.
The insurance company wrote their letter AFTER these emails, so are aware that there is still an unaddressed component.
I have emailed the person who wrote the DCBS letter with the relevant emails. But I’m not sure what else to do. I feel like I’m taking crazy pills. The DCBS claims there is no violation of Insurance Codes, which I can’t imagine is true, but I don’t know the law well enough to determine if there was and I don’t have the funds to hire a lawyer for this (although I am considering it).
The whole thing is just insane. Literally every interaction with this insurance has been an error. I have submitted to withdraw as a provider, and even my confirmation letter was addressed to a completely different person.
What else is there to do? I am sure we all want this to be over with, but I am out $1,000 not to mention hours and hours of lost time.