r8 controller works fine, but no sound PLEASE HELP

Hi there, my r8 as an audio interface isn’t working and I don’t know what to do. It’s really bugging me. I am able to use it as a controller, but I can’t seem to record anything on it, nor am I able to use it as an output on Cubase Le 7. If anybody knows how to fix this problem, I’d be much obliged!!!