New Arris SB6183 and New Comcast Account - No Internet

My daughter-in-law just signed on with Comcast - has a new Arris modem model # SB6183 and a TP Link Router. Everything appears good except for the modem getting signal. Since speaking with someone at Comcast is next to impossible...and our local office has been shut down....is there anyway to get this resolved without a comcast guy showing up to look at it with a $70 charge? And yes, we have powered the modem on and off approximately 8 times today, disconnected the router, have router signal to the Roku tv....etc, etc.