Left for Dead

I recently signed on with a new company. They are, for lack of a better word, very unprofessional. I went from Alabama to Texas to drive their truck. They didn't even have my truck ready. It didn't even have a mattress in my day cab. They made me leave with my first load without a fuel card! So, to get to the real issue... I've driven from Texas to Tennessee with my first load and the truck starts to run hot. I pull over (going up a mountain and very close to the edge of the highway mind you) before my gauge goes into the red so I don't cause any real damage. I call the company to let them know what's going on and they immediately accuse me of trying to tear up their truck. I assured them that I did my pre-trip inspection.. the coolant levels were fine. They said they would send someone by five the next morning. No one showed. A little later that morning an auto-diesel mechanic stopped and took a look at my truck. He told me a fan wasn't working. He offered to fix it. Long story short, he fixed my truck in a Hardee's truck stop. He said the normal price for that kind of work was around $5,000 but he only charged me $2,800 because the guy and myself became cool on some common interests. So, I let the company men know the price and they went crazy! They cursed me and said that was an outrageous price and they weren't going to pay it. After 3 days they sent the payment through Western Union, but then requested a refund so it never went through. I'm stuck in Tennessee with no money, this guy really wants to seize the truck for work done and no payment but he won't do it because he knows I'll have no where to go. I don't know what to do. I feel like this company has no regard for my welfare. If I leave with this truck, I could go to jail. They left me hanging.