Physician assistant made us take our baby to a pointless lab test and now we owe an expensive co-pay

At the end of our second or so pediatrician appointment for our newborn son, the physician assistant who met with my wife and me told me to make an appointment to have an ultra sound done on him to check for infant hip dysplasia. At the appointment, the technician was very confused as to why the physician assistant wanted us to make the appointment. I said I made the appointment because she told me to and so I thought it was important. Later on when I talked to the actual pediatrician about it, she was also very confused as to why the physician assistant made us do this. She said there was no reason for it because this test is only done when the baby is breach, which my son was not.

So it turns out this test was completely pointless and now we owe a co-pay that’s over $200. Is there anything I can do about this? This is just one of several outstanding hospital bills we owe that we’re struggling to pay. I quit my job to be a stay at home dad after the birth so money is much tighter now. There is a financial assistance option offered by the hospital but my wife’s salary is just barely too high for us to qualify. We live in Virginia and have CareFirst Blue Cross Blue Shield.