There's no way they can force you to work at another terminal. Tell them you absolutely can not do it this time. If you don't mind helping out other terminals from time to time that's cool but to try and force you is just stupid. Unless you signed up for one of the positions (usually in bigger terminals) to go and help other terminals they should not be able to force you into working at another terminal against your will. If your TM will not listen call Columbia and talk to them. The situation should be corrected very quickly once corporate gets involved.