I went through a situation similar to yours, and encountered an additional discouraging factor: YouTube seemed to threaten to take down my channel entirely if my appeal was to be rejected. There was also no real option for "the person making the Content ID claim obviously doesn't own the copyright to the work in question" (in this case, the famous "yeah! woo!" a.k.a. "think break" sample; the Content ID match was from what seemed to be a remix of "It Takes Two"), so I was at the mercy of whatever opaque process YouTube deemed fit to review my case - and was a bit spooked when it came to potentially losing my whole channel (and who knows what impact that'd have on my broader Google account).

Thankfully, I was able to find the contact info for the Content ID provider in question - and within a day of emailing them they pulled the Content ID claim, noting that the customer of theirs who uploaded that think-break-containing song did so in violation of the company's ToS (which specifically forbids uploading music containing common samples like that for this exact reason). It ended up being a happy ending, but it still left a sour taste in my mouth w.r.t. YouTube's policies and practices when it comes to Content ID and copyright claims in general.