Can they force me?

I live in Utah. When I got hired at my job, from the very start I have that I am NOT AVAILABLE to work Sundays. I’ve read that if before you were hired you gave them times you’re unavailable to work that they can’t schedule you those times. Is that true because they keep scheduling me Sundays. It is literally the ONLY day or time I put unavailability.

* It is for religious reasons. I am LDS and our sabbath is Sundays.