<prompt> Human: I purchased a used car, signed all the paperwork and drove off. A few days later I got a call and they said they had to change the contract and needed me to sign the new agreement, my APR went up a bit but they lowered the price of the car to keep the payment the same. I was iffy about it then I got a letter saying they couldnt get my car financed and i need to turn it in ASAP. I was sorta happy with this cause I changed my mind on the car, when i took it in today they told me I couldnt turn it in and I have to keep it, because they did find a bank to lend the money. But the letter says they want the car back and I could surrender it, can they go back on this signed letter idk what to do.Edit: Thanks for all the input guys. Im sitting in the dealership lounge waiting for my check back. I spoke to a attorney and he told me to drive to the lot tell them they sent me the letter voiding my contact. Leave the keys get my check and leave and if they try to withdraw my down payment that my lawyer will give them a call. They agreed and Im feeling way better now  <response>: This is a typical used car dealership scam. Google it, its all over the place. It even has a name, yo-yo financing.They let you take the car, the APR falls through, but what it really means is they are marking up your new APR with far more profit for them.The best thing for you to do is go out now and find a bank that will give you a car loan. If you go back to the dealer with an approved loan in hand for the amount on the bill of sale, theres nothing they can do.You should also be able to return the car. The dealer will do everything in their power to charge you for the use of the car for those few days, so you will walk out owing money. You should check the laws in your specific state or talk to a lawyer to know your rights. In most states, the dealer is obligated to either honor the original loan terms or undo the deal entirely. 