It IS a line-level mixer, right? If so, it ought to work. Have you tried hooking the mixer up to other equipment? Maybe it's borked.

Audio mixing revises and refines multiple tracks into the audio you hear in films, TV shows, music, and podcasts. With the great diversity of audio mixers available, it can be difficult to decide ...

Your phone's mic is fine for quick audio memos and the like, but if you want to record music on it, you need something a little more robust. Roland revealed a palm-sized audio mixer at CES in 2017, a ...