consumer alert for car buyers. You drive it off the lot, but they yank it back like a yo-yo. When is a deal not a done one? Brian ross investigating this incredible stuff. Reporter: It's a classic... See More
consumer alert for car buyers. You drive it off the lot, but they yank it back like a yo-yo. When is a deal not a done one? Brian ross investigating this incredible stuff. Reporter: It's a classic children's toy. But in the car business, the term yo-yo means something different. It's a growing practice when customers leave with a new car and are told they have to bring it back, yo-yoed. Often to sign a new and expensive deal. Janay smith said she was yo-yoed. About a week after showing her family her new car, the dealer told an angry janae smith, the deal was off. I figured once I signed the contract and he signed it, the deal was done. Reporter: When they decided to mess with jenee smith, they made a mistake. They find the right woman that was not going to take the crap from them. Reporter: Jenee took us along, wearing a hidden camera, to the dealership where she bought the car. The salesman told her the deal had to be redone because the financing fell through. We can do a new contract, a new deal for you. And it's going to be through here. Reporter: The catch, she would have to put down $300 more to keep the car she had fallen in love with. Reporter: A yo-yo goes down. And a yo-yo comes back up again. The car goes out. The car comes back. Reporter: Florida to car dealer earl stewart, said thousands of customers are being yo-yoed. Most with financial problems. These are the people that are vulnerable. Reporter: As we saw when we want back to the dealer. Mr. Hightower, she bought a car and now you want more for it saying he had done nothing wrong. And she had signed a document, promising to bring the car back if the financing did not go through. Reporter: She doesn't have a document. She do have it. Reporter: Can you show it to me? No. I don't need to show you anything. Reporter: And he refused again and again to show the document to me, until the owner showed up and made it turn it over. Give it to him. I don't care. We have nothing to hide. Reporter: And then, the truth came out. She didn't sign this. It's signed by you. You signed it. She didn't sign it. You tried to pull a fast one on us, sir. That's why you don't want to show it to me. She never signed it. Okay. Reporter: Vindication for jenee smith. The car dealer industry group says the vast majority of car dealers current without mistakes or conduct. As more as men buyers go home before financing is complete, consumer groups say beware of the yo-yo. On "the lookout" you'll see what happens next in jenee smith's battle with that car dealer. I want brian to go shopping with me. What are you doing this afternoon, brian? Ready to go. Thank you. Time, now, for the weather.
This transcript has been automatically generated and may not be 100% accurate.