I am private messaging you. I have read many essays that overstate interest in an area of study and overstate goals: often young people say they want to cure cancer, that kind of thing. You may have overstated something about your interest or accomplishments in physics and then didn’t have the goods to back it up when they asked.
But I doubt very much that is the reason for the deferral. As Gibby said, admission rate is very very low for internationals, and only something incredibly impressive would have helped you get in early(which they asked for to make sure they weren’t missing something). I know your environment doesn’t offer research opportunities, and no one would reject you for that.