I'd do a marketing campaign (Flyers, ads, etc... but nothing crazy) highlighting the deceptive trade practice. If they are stating that you went out of business and are redirecting, that may even constitute some form of fraud for misrepresentation as they are basically pretending to be you and in pretending to be you, channel your business to them. You might have a legal case against them, so a letter with some strong verbiage from a lawyer may be enough to scare them...