Zac Brown‘s ex-wife, Kelly Yazdi, is not backing down after the country star went to court seeking a restraining order requiring her to remove social media posts that he alleges are defamatory and violate an agreement. In a new response online, Yazdi says she “will not be silenced” despite Brown using his “vast resources” to shut her down. “No one — not even Zac Brown with all of his money, power, celebrity, and lawyers – may silence my right to freely express myself through art or, although I have to date declined to do so publicly, to speak about the circumstances of our pending divorce,” Ya…