Also, could you check with Anderson, Riddle & Kuehler, LLP, to see if they're familiar with Rule 11 of the Federal Rules of Civil Procedure?
And, practicing in Texas, they may not be familiar with California Business and Professions Code §§ 17200-17210 (relating to unfair competition and anti-competitive practices). Perhaps you should suggest that they consult with California counsel regarding the wisdom of sending threat letters in bad faith to businesses based in California, and the liability associated therewith.
--A disinterested party.