Got an automatic recording with no chance to leave a message.  The last outfit (from Florida) who continued to call AFTER agreeing that they'd put my number on the Do Not Call List (a legal obligation, but these are fraudsters)... I solved the problem by getting a live person again and told them I would blow this whistle whenever any of them called, after which I BLEW THE WHISTLE INTO HER HEAD.  It worked for months.  Now, they're back again-- a different setup.