Gigabyte Internet Extender Setup

[garcessist]

So I recently got FiOS gigabyte internet connection in my house and I also have a FiOS network extender WCB3000N.  When I had the FiOS triple play the Extender was plugged into the COAX and would just create a wired connection and wireless connection where it was.  Now my issue is that my extender will not pick up the new network.  The tech on the phone told me it will only work if I have the extender plugged via internet to the router it will not work via coax plugged to the router and the extender plugged into the coax upstairs.  The service tech at my house said it should work via the COAX.  I am not sure what to believe because I've used powerline adapters and MoCA adapters.  So my question is who is right?