Unable to Change Wifi Network Name and/or Password

I recently noticed my wifi network name and password reverted back to the defaults printed on the router (a TG862tg).  I have changed them successfully in the past, but am unable to do so now.  I have tried via the Xfinity website repeatedly and get a message indicating success and telling me the network changes will take about 45 seconds, but the wifi name and password never change.  I also tried on my iPad using the app with the same result.  I have pushed the reset button on the router for 30+ seconds, unplugged the power for 5 minutes, unplugged the cable, and tried restarting the router from the website - all with no success.  I have also tried changing just the name, or just the password, and tried using a more complex password with numbers, mixed case letters, and characters.  No luck.  Any ideas?