I have seen something similar happen to a co-worker who was starting at the same time as me at a new job. When he was hired, he was promised a management position with a higher salary than other developers, including myself. After working at the company for a couple of weeks, the company said they did not need him as a manager and wanted to reduce his salary to be the same as other developers. The guy ended up going back to his old company and getting his old job back because he was not willing to drop his salary requirement at the new job.