DMCA request--should I protest?

I just received a DMCA request for a book review on my website (it’s at least five years old). I know book reviews are protected under copyright law. I did use the cover image, but I also think that is protected.

I went to Google’s protest form, which states:

“Please understand that your contact information will be forwarded to the original complainant”

What if this is just a malicious phishing request in order to get my info? Is this worth filing a protest, even if I’m in the right? I’m not ever able to see if it’s the author or publisher filing the complaint (I can’t imagine they would since it’s a positive review).

What would you do??