American Auto group Committed check fraud, purchased services and parts and stopped payment on check. Miami Florida

I am a hybrid tech that was called to this car lot to repair a non running toyota prius. Upon arrival the lady that works there informed me to and I quote " fix the car so it runs for a month or two so we can sell it"  I wrote up a estimate and she signed it and authorized me to proceed with the repair. After completing the repair and having the vehicle in good running condition, she then gave me a check for the work.  A couple of hours later I get a call from someone at this dealership saying that he put a stop payment on my check because he felt that what I charged was to much and that he could just do the job himself to save some money.  Now I have over 5 hours of my time invested plus a part that I purchased inside this car. Now I have to submit this fraudulent check to the state attorney.

These people should not be in business , they should be in jail.