Have you talked to your insurance? I received a bill for a hospital stay in the amount of $12000, after the insurance payments. I called the insurance and inquired about it, since I couldn't believe that I still had to pay so much. They looked at my records and told me that the hospital made a mistake when they submitted their claim. They used the wrong codes. I was advised to call the hospital and have them resubmit it to the insurance with different codes.
I did, and then received a new bill for $ 150.
Maybe there was a mistake when the hospital submitted the claim?