TG862G modem, no dial tone

I bought my own new TG862G, and ordered internet and phone service last week. Internet was successfully activated last week and continues to work fine.  My phone number was ported from CenturyLink, and I believe the porting and phone service activation with Comcast has been successful because I see the phone number in my account view, and it also shows a missed call log.

But the problem is that I still have no dial tone form the voice line on the modem.  I spent several hours with chat support and the last info I got from them was:

"there is an error associating the phone number on your current modem"

and

"Basically, the system has detected that the device you are using is a Comcast device. Thus, this may create conflict on registering the device into our back end. It might be issue with the phone port as well in which it does not get signal from the back end."

I explained that the modem was my own and is compatible according to Xfinity compatibility website, and they agreed.

When I do a reboot, everything looks to be OK for the hardware. Tel 1 and Tel 2 lights flash for a few seconds each and then go dark.

Any ideas?