downloaded movie missing

what happens if you download a rented movie to a labtop. but you want to watch it on a mac computer. with the same account?

my labtop can't play the movie. my main computer has no movie just the bill of it.

what good is a rented movie if you can't watch it every you want. after all it's rented to your account. i rented on friday and now it's monday and still didn't see the movie. feeling ripped off.