Live in Florida. Auto Ins & Health Insurance

My daughter was in an auto accident, she was a passenger, we did not have med pay on the auto because the auto insurance took it off without our knowledge but we still had the liability which had a limit of $10,000. The auto insurance paid 80 percent of the medical bills, the health insurance should have paid the balance because the balance was less than the amount they would have normally paid. Why are they saying I owe my co-payment if the amount they had to pay is less that what they would have had to pay without additional coverage! Doctors office is billing me for co-payments.