The document already exists where you want it. You just need to do the
right thing to access it. Use the URL that you get from your code, but
don't include the last part with @"filename."
Pass the url to this method on the file manager:
- (NSArray *)contentsOfDirectoryAtURL:(NSURL *)url
The NSArray contains NSURL objects which point to the files and folders
in that directory. Use the URL of the file that you want and open it as
appropriate. For more info, see the NSFileManager documentation.