How to find missing file on Newsgroups

[Black Keys]

I downloaded a batch of files. All compressed in rar. I am missing a particular part and i cannot find it on Newsgroup. Ive had this happen to me a couple of times with few different files. What do i do to solve this problem? Or How do i get this file.

 

[growing cub]

If it's a scene release, you can request it on IRC. Many tutorials on FST

 

[Cruiser]

Or download that rar from a torrent site or find the par files and repair it.