you say you filed and nothing happened. that doesn't make sense. how long ago did you file? did you give a copy to that idiots boss? what did he say? did your grievance go to pre panel yet?
like others have said, you would probably have no problem getting several other people to sign your next grievance. I would file everyday this person spoke to you like that.
call the 1-800 line. believe it or not that usually works very fast.
the first time this happened, you should of warned the supervisor that you would first go to his supervisor, file a grievance on every instance, and then call the 1-800 line.
if you conveyed this in a professional manner the problem would not exist now.