When considering a sprint, time and points are approximately related and the coefficient is the velocity. When considering several sprint, the relation between points and time is more accurate.
But if you take one user story in particular, it's not at all related. I would like to be able to have a pretty complex user story that doesn't take that much time, or (more common use case) the contrary : a user story that is not at all complex (points) but require a lot of time to be completed.
Customer support service by UserEcho