Strict NAT no more what I do.

Recently been playing more FPS games (Call of Duty) and I cannot get rid of the Strict NAT once I upgraded to Cox Panoramic. Cox provided a Gateway and its been stressful. Here is what I have done so far:

1. Port Forwards for Call of Duty.

2. Disabled DMZ.

3. Switched on/off Upnp. 

4. Allowed access through firewall.

5. Ping the server and ping google - all good no packet loss until the evening which causes my server latency

6. Made a strict IP

The only thing I can think of is that its being blocked by Cox (which some ISPs do) or since the provided Gateway is a modem/router is there a double NAT going on I don't know about?