Student rebate

Got my Mav last week. Based on the ford website I told the salesman I qualify for the student rebate (medical residency, which is listed as qualifying on the ford recognition page). They invoiced and financed the car with that rebate. Now the salesman is asking me for a certificate approval number. I sent all my info to ford but they won’t approve it. I don’t think they really know what a medical resident is. Anyways. The saleman hinted at they’d have to revoke the rebate. Is that possible? Car is already financed and off the lot.