Am I owed money for doing a trial at a restaurant?

I'm a student looking for work and I applied to be a waitress at a local restaurant. I had an interview, then they called me in for a trial in which I did a 3 and a half hour shift. Greeting customers, clearing tables, taking orders etc. They said they'd call me back but never did. This was about 2 weeks ago. So I know they don't want me, which is fine. But my Mum's now on my back to get paid for the work that I did. I'm scared to ask for any money though. I'm a shy person and hate confrontations in any way. I want to just leave it. Am I actually owed money?