Have car from dealership and no contract.?

i went to dealership to buy a car and it was late and i gave them drivers license and pay stubs and they told me to take the car and that they would get approval by saturday. i went on saturday and a guy said approval has not come through yet. now i get a call from sales guy there saying i have to go by tonight or they will take car back. I asked how much was i approved for and he doesnt know. What could be going on.