Contract working hours HELP!

It would be difficult to address the issues you raise without knowing

1. in which country you are located.
2. what your contract says, including its period of validity
3. what--if any--promises your employer has made to you, and whether those were made in writing or made by someone with the authority to make them
4. whether you are the only person who has been treated in this way
5. whether your employer has an employee handbook and what it might say about relevant details of your situation

Then, I'd also want to know if your real problem is working shifts you don't want to work, or working at a job you weren't hired to do without receiving the advancement you were promised.

If your contract is for doing work that you have never done it may not be valid for your current situation.

The underlying issues may engage labor and contract laws that could be larger than your experience. If that is true, a crowd-sourced answer will be of minimal use to you moving forward.