What does "blocked" and "everything" mean, exactly?
There is no need to create any firewall rules. The G1100 should act as the DHCP server to the local LAN and it should assign IP addresses to connected devices. An ordinary consumer-grade router does not need any ports opened up or other special settings to work with an OBi device, and (unless the Trump FCC has changed things), it's illegal for Optimum to block you from using the service, so I doubt they are doing that.
Does anything else connected to your router connect to the Internet and work properly?
Pick up the phone attached to the OBi and key in ***1. Does it play back a local IP address? If not, you have a fundamental problem. It could be something as dumb as a damaged Ethernet cable or plug or socket, or one that is not properly seated.
If it does get an IP address, then what happens when you pick up the phone and key in **9 222 222 222?