I agree, toll roads charge based on the license plate or scannable toll pass. Did you have a toll pass in your old car? Even if you did, they should be able to see the license plate doesn’t match your account. Also when you called them did you call the number listed in the letter you got from them?

I would try looking up the company’s number online and calling that. Then if it is a legitimate toll charge, doing what dan1101 said should suffice. I definitely wouldn’t send them a bill of sale or other paperwork. If they’re still stubborn about it, a letter from the dealership that you traded/sold that vehicle on (date) might work.

Having been fooled by many a bag, this made me chortle

I’m having a hard time choosing a favorite, these are all so great. The resplendent and blue owls both really drew my eye as I was scrolling through them all.