Just ordered the Digitone Call Blocker for $99. on Amazon. It will do what you want it to.
Check it out:http://www.amazon.com/Digitone-DCB10-Call-Blocker/dp/B009RVYEZ0/ref=cm_cr_pr_pb_i
Comcast is too busy making money to take care of their costumers, so you have to do it on your own.
