Problem: Your ISPs DHCP does not function properly

I've tried multiple resets on both my modem (ARRIS SURFboard SB8200) and WiFi router (Asus RT-3100). Tried Comcast chat support and they couldn't come up with anything...I think all they did was send reset signals. And when that didn't work they said someone has to come out and check it out.

Is there anything else I can try? Not scheduled to come up until tomorrow afternoon.