Ford Repair: misdiagnosis, and refusal to refund money, small claims court, fine shape

Question
Hello,
Recently, I took my car to a repair shop for one specific bucking problem problem.
The shop called me and informed me that they had found the problem, the. radiator needed to be replaced, and the transmission needed flushing. the total for the work was $691.00
I approved the work to be done, and came back to pay for and pick up my car when it was done.
Immediately after getting on the road, the car began doing exactly the same problem.
I brought the car back, and retrieved my old radiator.
Upon examination by another shop, the radiator was in fine shape.
The manager of the shop has denied my request for a refund of the work done, nor will he consider
applying the previous charges to the new work that he now says needs to be done. he is now saying he cannot even find the problem because the car is not registered.
In summary, he misled me to believe that the previous work done would solve the problem, that is why I approved it,
and upon pickup, and after payment, the problem was still there, meaning he mis-diagnosed the problem and
charged me for something I did not need.
So my question is, what are my rights, in this situation? and what should be my course of action?
Thank you very much,
Christa Wu

Answer
if you can get a second shop to confirm the radiator was o.k. and confirm the problem you were having is still exsisting then small claims court. this is getting to be a very common problem by under-trained technicians. Most judges will appeal to your side, on that note- if the first garage see's a court letter to appear or that you are going to take them to court- usually they give in pretty easily.. keep me posted