Some time ago I was making music for a movie together with a friend. It was a free of charge job to help her and to get my name "out there". Time passed, I forgot about it and nobody told me anything about it anymore...
Now I checked out on them, the movie is out from 2013 and my name doesn't appear anywhere. Not on their promos on YT, not on the website, not on the IMDB page, nothing.

Contacted them some days ago, no answer yet...

Because I'm basically a "ghost writer" without any kind of contract I can't do anything about it. So, lessons to be learned:

1. Always write a contract, even if it's for a non commercial collaboration.
2. Ask specifically for what you want in the credits.
3. Put a price on your work if you want to be taken seriously.
4. While in the process of working, make this a public matter if there isn't a "no disclosure" type of contract. (well, that's with a "maybe")
5. Never work with those people again.