Inspection Center Claiming Body Damage / Repainting for Car Sale Inspection

I've had an inspection center claim I've used body filler and repainted a certain part of my car and it has caused the buyer to back out of the sale. I've owned this car from new and have never had any work done on the body.

How do I disprove their claim? I'm considering getting an inspection done at the Ford dealership, but again, I'll be paying out of pocket to correct a shoddy inspection job.