Out-of-network service reimbursed as in-network

I had therapy at a clinic last in March-May 2022 and paid out of pocket and submitted superbills. My provider does not take any insurance, but there is another provider at the clinic who does. I just realized that the EOBs say in-network and that I only owe a $10 copay after they cover the therapy, and the coverage is about half what I was reimbursed for another out-of-network therapist I saw in February. Something else they sent to me when I appealed one of the claims that has a mistake showed the provider name as the other in-network therapist, so I assume they put in the clinic name and saw someone as in-network instead of putting in my therapist’s tax ID.

I called my insurance company twice and neither person I talked to was any help, just saying this is in-network blah blah. The clinic was no help, saying they can only provide me the superbill as they did (and their billing seems like a total mess in general). Anything I can do here? I spent $5500 and was reimbursed $1500 when I think I should have been reimbursed around $4000.