I can sympathize if your hands are tied by a big label. It sucks. But you've got a duty to explain what's happened and do some damage control.
You've been advertising this for weeks and a lot of outlets in the US, Canada, Australia and Germany published stories about the release. At the very least address the situation via Twitter or a blog post.
-Short of the Week
We must issue an apology to all the cinephiles here from the US and Canada. Originally, this was supposed to be a worldwide event, but the label pulled the film from the US and Canada at the last minute. We're extremely sorry for the inconvenience, and we hope to make up for it with some exciting plans for the future!