I am sorry about what happened to you at EWR. Sad to say I think there are three sides to this story: the GA side, the pax side and, the side no one told. You did cross the line by cursing. A GA can deny you boarding or any reason that they come up with. If you challenge it - guess who security and the powers that be will believe.
I do not believe that CO will do anything other than apologize to you and say that they will speak to the GA and the supervisor. Good luck with getting a refund - I do not think it will happen. As others have said on here, you never piss off the GA or anyone in authority at the airport because they have all the rights (another reason for a pax bill of rights) not you.
The 800-we-care line or writing to LK isnt really going to get you much other than perhaps an apology. As an example: More than a year ago I asked for a security pass to use the PC. The CS agent at the counter said they do not give those out after 9-11. I asked for a supervisor (after calling the EWR PC who advised me that they do give these passes out). I told the supervisor that I had the number for the EWR PC club and he can call them to check his information as I was sure he had incorrect information. He responded in a not so friendly tone saying that I was wasting his time and that he had more important thing to do. I must had pushed him too far when I said that a simple phone call to the PC would resolve this and he responded by saying if I took this further he would call the police (not security) and have me arrested. I backed off at this point and walked away. I later sent an email to LK and I receive a call from someone in his office apologizing for the incident and to assure me that the GA and the supervisor would be told that if someone has a current PC card they should be given a security pass. I waited almost a year to ask the same GA and maybe a month or so later the supervisor for a security pass. Guess what answer I got - yeah the same -we do not give those out since 9-11. One of two things happened here - either the person at LK office never followed through or the EWR agents dont want to be bothered (i.e. do as little as possible to get through the day).
Kinda sucks but we dont have much of a choice if we want to get from X to Y.