Planning claim natural sandstone is artificial, help!

I was actually thinking that this guy is providing false information (defamation?) about the product to members of the public, therefore causing damage to the reputation of my business. It is also indirect allegation that my company is misselling artificial sandstone as natural. Moreover, as the guy was provided with samples and datasheets, common sense tells that his behaviour is reckless and potentially deliberate. I think I should be seeking legal advice on this.

 

Yes, I have been in the quarry myself and have taken all the samples. Cannot be more certain on this.This is not something that he can be sued for, but the situation definitely warrants requesting him to correct mis-information. If not, then a formal complaint to his Council is the correct course of action methinks.