if you buy a pre-owned vehicle based on a certain APR, is the contract void if the bank does not honor the APR

Question

an auto mall sold my sister a car based on a certain APR (this is in California) and two weeks later called her to say that the bank didn't accept the APR and needs to refinance the car - she said no and they told her she had to return the car; she is returning the car and is now concerned that they make her pay for it (I told her definitely not) and that it will affect her credit and ability to buy a new car.

Answer 1

If they take the car back it's theirs....
Read the contract closely, (should have done that at first).

But generally speaking she will probably be ok.
Did she have a trade in? If so this is where it gets sticky.
I've seen car lots take the new car back, but they have already SOLD
the trade in car......