Try and ask to speak to a ‘case manager’ or specialist!

That has helped me in the past? Staffs have worked hard and long de-tangling some of my insurance’s messes in terms of claims for IVIG [and, they were VERY messy!] But they got worked out in increments.
Thing is usually? That that ONE good person you got has since been promoted and well? You have to start over again. Or…you simply get no response to voice mail or any other attempts to seek expert help. You need NOT your average clerk to deal with such squirrelley issues! And don’t take no! HOLD until you get someone or if disconnected…call back and ask for a supervisor BECAUSE you were disconnected!
It’s time consuming, yes. Stressful? Sort of. Frustrating, definitely. Patience required absolutely! Don’t know about anyone else? But the pile of papers I have to keep ‘near’ me for reference? ALWAYS seem to collapse at the wrong time! Well? On the good side? I don’t have to stand in line for an hour or the like!
Good luck! Sometimes you get GOOD insurance staffers! When you do? Worship them! I mean it!
May Santa be super to you in some silly way! HUGS!

Yep, It feels soo good when I stop beating my head against brick walls! Those endorphins! Good stuff!