Am I legally entitled to an EOB that actually has an explanation?

TLDR: Husband had a claim re-processed and the new EOB is just a sheet with a refund amount on it. The refund is at least a couple hundred short.

My husband had a dental procedure in December 2022 that was in the low mid-thousands USD. According to our dental insurance company (henceforward appropriately shortened to DIC), my employer called DIC a few days after the surgery to cancel his dental coverage for the month of December. My employer has no record of this call. After a few calls, we now have this sorted out and his coverage was reinstated. The claim had already been processed as non-eligible though.

When the claim was re-processed the first time, it came back as him still not having coverage, this time supposedly because when the dental clinic submitted the claim they put him as my child and not my husband. Several calls and a month and a half later DIC has pre-processed the claim again.

Except, the new EOB for this claim does not have any “explanation” part whatsoever. It’s the old EOB, which says he’s not covered, with an additional page at the front containing his doctor’s name and a refund amount. The refund amount is at best, a couple hundred lower than it should be, and at worst, around a thousand. I don’t know how our policy’s been applied, but there’s no combination of 50% and 80% of coverage that would give the nice round number our refund was listed as.

I’m calling DIC on Monday to request an actual EOB. Before I call, I want to confirm, am I legally required to an EOB that has an actual explanation?

I have half a mind to report DIC to better business bureau for the hoops they’ve made me go through to just get this far (among other issues, such as not crediting my payment for an ineligible FSA charge until I called about it twice) but I don’t know if that would do anything since DIC isn’t registered with them. Please advise!