First, you need to write a dispute letter to the three credit bureaus explaining this story. As a lesson in this, ALWAYS resolve your matters as quickly as possible. When you dispute this, I can imagine that they will argue that you did move in an then quickly abandoned it. There are ways to put your self in a good position by writing to them after this happened to confirm that they would not let you move in, so that they can't change their story later.
As far as being denied, that is completely up to the individual landlords/property managers. There is a rental history database that some subscribe to that this can also show up on.
I recommend you speak to an attorney in your area to see if you have unfair debt collection claims against the former landlord that can give you leverage.