If the blind either is not level or if it does not fit tightly to the headrail when the blind is up there is a way to reset the cordless mechanism. To reset the mechanism, bring the blind all the way down to where it can not go down any further. locate the cords that are operate the cordless mechanism and pull them slightly and snap them back. Your cordless mechanism should now be reset and your blind level.
Here is a video that shows this process.