CV will likely know that, and call your bluff. Doesn't hurt to call - worst case they connect you to the disconnect department, instead of the retention department. -- NOTHING justifies terrorism. We don't negotiate with terrorists. Those that support terrorists are terrorists.
That usually does not work. They check to make sure FiOS is available at your address. The phone rep has your address and can plug it into the same online Verizon tool that you can use to verify FiOS eligibility.