:-/ sounds like insurance company shenanigans of some kind. Good luck. Unlike tinnitus, E-tube things causing obvious symptoms can be visualized pretty well, it's a mechanical problem, and there are things that can be done.
Don't be surprised if the ENT wants to stick a scope up your nose; I've had this done, and while it wasn't pleasant, it's relatively brief, and not painful. (I thought it was uncomfortable, but much less than when I had a scope down my throat to my stomach without anesthesia... let alone the time I let a doctor jam a camera up my yingyang to look at my bladder... if I ever have THAT one done again, they're gonna have to knock me out).