I am a lawyer in Ct.  The rules are governed under the fair debt collection practices act - federal law.  If you send a cease and decist letter the company should not be calling you.  You may have a cause of action against it for violating the act.  I would have to know more details and need to see the letters you wrote.  but if you did send the proper letters then the creditors should not be calling you or any number related to the account.