Harmful website need help

We started to get calls from persons asking for products we do not sell, so we found an individual who uses a website with our phones and direction as it´s contacts is sending this contacts so we tried to let them now we are not part of his business but the domain registry organization told us they are not capable to contact the client to recommend a cease and desist action, so we need someone to tear down their website and clean our company name from his dark business