Hello, I submitted a DMCA takedown request to a user on here
I don't have any idea who you submitted that to: WordPress.ORG (this place) does not host anyone's blog or web site. This place just provides the opensource software for people to use.
I do not feel comfortable providing information on the whos and whats as this person has threatened people I know.
That does not sound like a good situation to be in and I understand why you do not want to post that information.
If you mean a WordPress.COM (which is not this place, see this link by way of explanation) then you can try reporting abuse to this site:
If the site in question in not a WordPress.COM site then you'll need to identify the hosting company and communicate with them.
This site may assist you with that.
Good luck and I hope you get this resolved.