I hope Mark Manson reads this, and then fires his staff, or at least yells at his publisher's staff.
You are clearly not in violation of any copyright. And so, they, at minimum, are just wasting your time. I guess they couldn't be bothered to waste any of theirs looking into the actual case.
Word of mouth advertising is the strongest form. Clearly Mark Manson, or someone who represents him is a complete Jackass. And for putting You threw the ringer, in my book he
or they, are a complete and utter looser with lifetime tenure.
Now if Mr. Manson wants to come after me for my review of him,
Lol:)
Spot on mate. Sadly this seems to happen a lot with DMCA requests though.