Until then you can and should do (or say) nothing until you receive proper notice -- which you then will bring to your new lawyer in a very timely manner.
If you put this in the hands (fins) of the sharks at this early stage they will own you for no good reason from your point of view and may turn this literally into a Federal case at your expense.
There will be plenty of time for that later if this whole affair is anything but a scam. BTW, the question of exactly how and to what extent the claimant has been damaged by you comes to mind, for openers.
Finally, you should contact your (and his) Secretary of State and perhaps the US Department of Commerce (specifically, the PTO and he Federal Trade Commission) to inquire and report re: a possible interstate internet scam. The "authorities" do not take kindly to weasels representing that they have IP protection that everyone else goes to the trouble of obtaining through legal channels (for a fee to the gummint, of course).
Don't lose any sleep over this. All the best....
Thanks, man!
What has yet to be answered is can I sell advertising to Minnesota businesses if I live in North Dakota, and my website is based out of North Dakota?
My website is www.invominnesota.com
His is www.fishingminnesota.com