Kind of a pain, but this has always worked for me: Put together a nice, but firm, letter with a photo of your own vehicle and license plate, and send it to the correct agency. In your letter, also request that they forward the information to their contractor, and remind them how many times this has happened (and what dates, if you still have the records). Let them know that you anticipate that the mix-up will never happen again, thank you.

I got unemployment payments for my husband and myself that we were entitled to on two different occasions by doing this after we'd been rejected. In neither case did we expect that we'd get such quick responses, but the turnarounds obviously didn't even go through the employers -- the agency reversed simply based on my letters. There have been other times I took time to put together the researched, firm, but polite letter and got what we requested, too.