I have the same problem. I contacted the dealer and he said he had no idea that used cars could claim a credit. He also said that the IRS system does not let him enter information into the system more than 4 days after the sale and therefore he cannot correct it. He checked with other dealers and said it was a common problem. Somewhere in his checking he was told that the IRS is aware of the problem and that the IRS will send a letter to people whose returns were rejected for that reason within 60 days of the rejection with the instructions for what to do. The instructions will apparently say to include some of the documents of sale that prove eligibility.
I have no idea if any of this is true. It seems the path forward is to file without the credit, wait for the alleged letter to arrive or any more guidance that may surface and then file an amended return. Or paper file with your idea of what supports the credit and see what happens.
For those recommending small claims court, who are you taking to court? The IRS? The dealer? The dealer doesn’t have the money owed, the USG does. I don’t think small claims court handles tax matters.
