need help resetting my Comcast Business Gateway reset.

Hi,

I have a model SMCD3G-CCR   I upgraded my wi-fi router that came off of this unit, and in checking everything, I found I cannot get into my Comcast Business modem to check the firewall settings. 

I tried to reset the modem several times, and it is not defaulting back to cusadmin/highspeed as my documentation is showing it should.  Please advise if you can do this from this message board, or should I call the help line?  Does Business Comcast for internet have a chat forum to talk to a live person? 

Thanks for your help!