OK, I'm with everyone else.
IF you can PROVE all that you say, make sure you have it all down in an organized fashion. We all believe you

but you MUST have the paper/picture/recording trail documented.
- I don't know that you want to get the lawyer. They will charge more for 1 hour of their time than what you are out. You can sue for actual loss and lawyer fees but if you lose, you are out thousands and thousands. And they would probably counter sue (unless they know they got caught with their pants down) and hang their lawyer fees on you if they win. This is what scum like your ex propane dealer rely on when they screw you. A lot of people will eat their several hundred loss rather than go to court, SC or 'big'.
- Go to small claims. The more rational you are the better. If they get hot, it only makes them look worse.
- Be careful with the letters to the editor or whatever, you MUST be able to prove what you say or they could sue you for libel when they lose business.
Back to the original premise - IF you can prove it: Whether or not you go to SC court, but especially if you do and win - put it in the letters to the editor. I suspect a LOT of people will read it and say "I'm not the only one?!?"
Also remember that the person who cuts your hair (and that of your SO if you have one) knows WAY more people than anyone else in town. I work for a large company and the lady that cuts my hair ALWAYS knows something is up before the 'little people' at the plant and her info always turns out at least 80% accurate as to the details. Management can't/won't tell us but they blab it either to their hairdresser or tell their spouses and they talk. Make sure you rant a little bit to them. You don't need to go into all the details you have here, give the RD condensed version. Word will get around and you might hear "I have heard they were sleazy" from them as well.
Send the people who own and work for the propane company to the unemployment line. The legit workers will get jobs with the other propane companies who take over the low life company's customers.