I've heard of constructive dismissal, but the reverse...whatever, it sounds a pretty crappy way for your head to behave.
I don't know what procedures are in place and whether you're in the USA or the UK, where employment law is different, but a contract of employment is binding for both parties - you and your employer. If it isn't being honoured, then you have grounds for complaint.
Are you a member of a union, and is there a rep you could ask for advice? If not, in the UK most legal firms offer a one-off free consultation on what used to be called the "green form" basis, where you can quickly establish whether or not you have a case and can then engage a lawyer if need be. In these cut-throat days some lawyers will even act on a contingency basis if the breach of contract is blatant enough to give a high likelehood of success at tribunal stage.
Good luck!