If your "modem" is actually a Ubee U10C018 as is implied by the config file, then it is a DOCSIS 2 End Of Life device ( »
mydeviceinfo.comcast.net ··· devid=15 ), and that may be part of your problem. Since there was a question (in Comcast's opinion) on whether that device was in operation, an EOL device will typically not be reactivated for use on Comcast's network once it has been deactivated ( »
customer.comcast.com/hel ··· devices/ ). If you don't have a Ubee U10C018, then you seem to have been sent an incorrect config file by Comcast.