Why isn’t Cox part of the group of telecom companies working to end robocalls?

It has been in the news the past few days that attorneys general from all 50 states and DC are working to combat robocalls with the new technology available and to offer free blocking features to all customers.  Included are Verizon, AT&T, Sprint, Comcast, Frontier, and about a half dozen more providers.  One report specifically named Cox as not being part of the effort.  Why is this so?  We receive a boatload of spam and robocalls that waste our time and attempt to deceive people, yet Cox missed the boat in getting in on this effort.  For many of us, we keep the landline in order to receive a bundle discount, but either 90% of calls received are unsolicited junk, or people just unplug the phone but keep the line.  Nomorobo helps, but is more of a band-aid if anything.  It is only about 50 % effective, and is totally useless on spoofed neighborhood spam calls where the area code and exchange match.  Just feel like the only solution is to either unplug the line, or sink extra $$ into buying phones with built-in blocking technology.