That’s an old dealership…
That’s an old dealership trick. I had one do that to me in the 80’s.
Trade-in was supposed to be fine for payoff. They waited 4 days came back at me for the money to payoff the trade-in or return the new car. Went to an attorney who told me since there were contracts, signatures, etc. the original deal was legally binding. He also told me I’d end up spending more than the price of the car to fight it. It’s a crappy way to do someone but the dealership doesn’t care. On his suggestion, I wrote down the VIN numbers of the vehicle I wanted. Took my trade-in back and flipped off the dealership. Went like 5 miles down the road to another dealership authorized to sell the same brand of car. Gave them the VIN number and told them where it was located. I did a new deal with them, got my new car back and got a much better deal.