Bell Ford service department unethical phoenix, Arizona

Here are the facts:

I brought my truck in for a diagnosis. I specifically told the assistant manager who was helping me that I needed to know everything that could possibly be wrong with the vehicle. He said it would be 99.95. I didn't hear from them for that day and into the next until I called. I said I want to make sure you are not performing repairs that I did not authorize. He said Oh no, but then tried to charge me 216.20 because they cleaned my battery terminals and tightened some wires. I was very thankful for the clean up but this was not the deal. They ended up only charging me 99.95 and that the guy said you won't have to worry about "that" repair. I drove the van home and the next day I drove to a job and right when I came home from that, the engine started to rough idle and smoke and lack power. Now it won't even drive down the road and has a worse rough idle and more smoke. I called them and they would not help at all. Won't pay for a tow back, won't back up their diagnosis and the head guy even said I didn't pay for a diesel diagnosis when my receipt says I did. They said my truck needed regular flushes and such. I have always changed the oil on time and filters. 120k miles, had it since 50k, 1999 powerstroke E-350.