Hi,
You are not talking directly to Comcast here, this is mainly a user to user forum.
Have you tried a quick 2 -5 sec press of the recessed reset button on the back of the modem/gateway, using a pen tip or whatever? Give it time for the lights to settle, see if that helps.
Otherwise try the livechat here:
https://www.comcastsupport.com/chatentry/?Trouble.VoicePhone.NoDailTone