Rights to require the company to honor my hiring offer/agreement despite a policy change?

I am an Ohio resident and approximately eight years ago I was hired as an out-of-state full-time telework employee. The only difference, between my hiring and that of my coworkers, is that I work out of a home office in a different state. My employment application references my out-of-state address, and I selected “no” to the question “are you willing to relocate”. My offer letter states that it is an agreement to telework outside of the state in which my employer resides. I also have a telecommuting business case document (2012) for out-of-state workers approved by the CAO and the DCAO listing myself as a case model for the need for telecommute employees. I am a performance-based employee, the same as all of the other individuals working for my employer, and have consistently maintained a high-performance review rating. Additionally, I live with a disability and working from my home office has allowed me to completely control the environment minimizing interruptions, like having to take time off from work. My home office environment also meets the requirements of my doctors ADA Medical Certificate and is what he has recommended I continue due to the success in managing my disability flare-ups. A few months back my Director suddenly decided to make a policy change, one which he feels supersedes not only my hiring offer letter but also the understanding conveyed to me regarding my positions security as being “just like every other employees’ position, just out-of-state”. Despite proficiently completing eight years, (with high performance reviews and accolades from customers), he provided me less than three weeks to relocate while offering no relocation assistance. In addition to the expense of relocating, the ADA accommodations he offered would create an unsafe overall environment for me.