Can I Stop payment for false diagnosis

Hi, I had a tech come over our house for a refrigerator issue, there was a $75.00 fee which is waved off if the tech does the job. Well tech mentioned what the problem was which was about a total of $750.00, and it would be ridiculous if he did the job. He recommend a friend of his which sells appliances and showed pictures from his phone. I paid for the visit, and checked the problem myself, it was never a compressor issue it was a fan. which I replaced myself. I called the techs company to complain and that I wanted a refund, which I was denied because tech did not perform the job. I explained what happened and all I was told was that tech will be fired because he stated to them all we needed was Freon (gas) and we denied it, but no refund. what is my position in this situation?