I settled on an employment case of not paying me. Part of agreement off the cuff is they are to hire me back. Now they wont, but I have email stating.

Unless the agreement to rehire contains an express duration term, your rehiring was "at will" -- which means that either party could terminate it at any time. As a result, the employer has no duty to re-employ your services for any particular time period and may elect to have that period be effectively zero. If you were represented by an attorney in connection with the settlement, you should confer with him regarding your rights.