Hello LV Jody ,
Its glad to know that the first port had been activated by Cox . If you would like to activate the 2nd port you need to contact ISP for the same to provide a different IP address.
Well its a cable modem where it requires a public IP address for each port , so IP address cannot be the same for both of the ports so in order to activate second port kindly contact ISP further.
Sorry for the inconvenience , as we don't activate the modem .
You can’t do that with a modem.
You’d need a router that supports dual wan input (and not wan port aggregation, thats different) with load balancing or wan failover depending on what you want.
Most consumer gear doesn’t support this and you’d be getting into business class gear (and more expensive).
Cox should be fairly reliable. If setup properly coax connections should be pretty rock solid. If its going in/out, I’d be contacting cox to fix it.