ISP DHCP Does not Function Properly

Hi, hoping to get some assistance here. I activated my service yesterday, moved the modem within my house--then upgraded the service to gig speed. After the upgrade, my connection dropped and I am receiving the error YOUR ISP DHCP DOES NOT FUNCTION PROPERLY. After reading additional posts regarding this, it appears the modem needs to be reprovisioned. 

When I activated service yesterday, it required contact with a tech support rep who took down my mac/serial on the Arris sb8200. Now, however, when I look at my devices through my account page--I show the mac address listed as the serial. Could this be part of the problem? Is there someone who can assist in re-provisioning my modem? 

@ComcastChe I've seen several replies from you regarding this.