I don't really have any suggestions other than to keep bugging the insurance company. I've noticed that at some point they figure the time they're expending in denying your request becomes counter-productive or they start losing money. It's almost like they have a big hourglass on their collective desk and when that last grain of sand falls they say, 'um, okay, we'll cover that for you.' And why couldn't they just agree to that from the start?
kathy