[cracell]

Was this not at-will employment?

While getting it in writing is good, it doesn't actually protect you. Vast majority of people are working at-will. Which means either party can change the terms of employment whenever. And if the other party disagrees then employment is terminated.

In this case meaning, if your contract says remote then they can change it to not remote at any time. That said, any company that will pull shenanigans like that you don't want to be working for anyhow as they don't respect you and that will impact you across all aspects of your work.