Joint Custody & Secondary Coverage

I have 3 kids with my ex-wife and we share joint legal custody. In our custody agreement I’m the one who has to provide health insurance for our kids. I’ve been doing this for the last 5 years since our divorce. My ex-wife remarried 3 years ago and now has 2 step-children and a 3 year old with her husband.

My kids were here with me over the long weekend in October and one of them got sick so I took him to the doctor. Today I got a bill from the doctors office saying that my insurance denied my claim. I called up the insurance and they tell me that my kids have other insurance coverage and that they are doing an investigation. I asked a lot of questions and they’re telling me that they may retract the payments for any claims they paid since the date they started being secondarily covered.

I called my ex-wife and it turns out that when she got married and had her kid that they put all the kids on her work plan and didn’t think anything of it. So for the last 3 years my 3 kids have been covered by both her medical and my medical. She (and I for that matter) had no idea this was even an issue. In that time they’ve all been to the doctor, specialists, and my 7 year old just had a tonsillectomy earlier this year. I’m in shock at the idea of possibly owing all these medical bills. Of course I’ve been doing some digging and I have questions trying to steel myself for the worst.

Is there any loophole/protection/exception for this type of case where it’s two separate adults insuring the same minors? Does the custody agreement hold any weight, like even though we both had insurance I had to be the one providing it?

It looks like HER insurance is the one that should have been seeing them due to the birthday rule but they’ve been seeing MY insurance… so does that mean her insurance can now deny everything since nothing was preauthorized and all out of network?

Then if HER insurance denies all claims, will mine likely continue to do the same? In that case, if nothing is covered am I the only one responsible for all the bills since it was on my insurance? Will they go after her too? How does this work in the case of minors? Can they cancel us for the future over this even though we are both in group work plans?

Give it to me straight, am I screwed or can this be fixed? Is there anything else I should know?