How to secure COX phone modem wi-fi signal & dropped calls

I have the

Voice/Internet Modem
Brand: ARRIS
Model: TM3402A

Seems to work BUT with dropped calls and the modem is "HOT"...  Meaning, the modem is showing up in "my wi-fi connections" BUT is unsecured.  I've looked at the tools and tips for both COX wi-fi and the phone service including the Cox wi-fi app.  Nothing is mentioned anywhere that I can see in the forums or online.  The phone modem and my Cox Gigablast are split into two indiidual connections from coax wall connection.  I only have one wall connection, so my connection options are what they are.

Any insight will be greatly appreciated.

LCW