Serve it warm with any dal, side dishes of your choosing. They taste well with pickle too.
One possible reason was not enough water. Was the prepared dough soft and pliable? Also overcooking on the hot stove could make it harder. --DK
Oh yes you can use rolled oats. and You can also use only Oat bran. As long as there is some components of Oats in the recipe to call it Oats roti, anything works :)