Just playing devil's advocate here, so don't shoot the messenger...

The difficulty would be in proving there was no infringement on the arrangement, especially if they haven't notified you which particular "work" you're supposedly infringing. The fact that you made a recording of yourself is insufficient to prove you were ripping off someone else's distinctively original arrangement. If they could narrow it for you, you could probably prove (with a bit of research) that any commonalities were ones not original to the supposedly infringed arrangement--if indeed there was any real originality in their arrangement at all.

Of course, first you have to know which work you're reputedly infringing, and in what way--conveniently, they don't bother to tell you, though they must know in order to make an assertion of possible infringement.

The best response would be to abandon YouTube for a service with less overreaching policies, making it the new YouTube and giving Google the thumb, or middle finger, or whatever snubbing digit you choose.