Insurance won’t send Dr office eob. Dr office says I’m responsible for the balance. Now the amount has been sent to collections and the Dr office says they can’t do anything

I have a medical bill from January 2022 that I have been trying to get covered by my insurance since I received the first bill. My insurance switched to a new insurance last February. I have all of the information saying that I was still covered by my previous insurance when I went to that doctor’s appointment. I have been going back and forth with the Dr office and my old insurance trying to get the appropriate amount covered. I called the Dr office today because I received notice that the bill has been sent to collections. They said that there’s a note in my file saying that the insurance company was going to send an EOB by fax but they said they never received it. I asked what I am supposed to do if they won’t send the EOB and they said the full bill is my responsibility. I tried calling the insurance company today, but they’re closed for Thanksgiving break.

Is it accurate that I have to pay for the bill if the insurance company can’t get it together to send the EOB? I’ve been fighting this for almost a year and it’s ridiculous. It’s stupid that my credit score has to suffer because a stupid insurance company can’t send a fax.