Modem LAN

We have a CR open to solve the following problem. We use the LAN on the modem to connect to our Firewalled network to test VPN.VOIP etc, and to separate WiFi services on the modem for users mobile phone's etc from the internal network. I do this because it gives me an external IP address. This all worked perfectly up until today. The modem was offline 2 times overnight unexpectedly. Now when I try and connect via VPN/VOIP it just hangs. If I try and connect to a web service running internally it never connects. If I tracert an IP address in our block it never connects. I can connect to anything outside of our IP block fine. Level 2 support say's it's not on Comcast's end. I'm the only one that has access to our firewall and I know nothing has changed for weeks. Any thoughts would be appreciated. They are send out a field tech tomorrow.