Pay Issues

I work in the Marketing Department for a large Telecommunications company in Florida. We recently went through a merger and my job title/pay scale was incorrectly assigned by our corporate office. They have me at 2 pay grades/job grades lower than I actually am. I have, in writing, the job duties for both my position and the incorrect title I was assigned and they are not related in any way. I've contacted my manager, director, the HR manager, director, etc and still, 3 months later nothing has been done. My director wrote to me in January and said they are in the process of fixing the error, but to date, I have not seen any change.
Thank you for any help you can give!