I don't think it works that way. If you have an account with anyone, you can't get them put on the "no call" list.
Now, if you had an OOMA instead of the landline, not only would you save a lot of money, you can "Blacklist" anyone.
I believe they still have to remove you if you request it from anything other than "business" calls relating to bills etc.
DirecTV has their own "do not call list" and they are very good about adhering to it. Just tell them no more sales calls and t hey will stop immediately. You can even "opt out" online. I oped out of everything and never even got my anniversary emails. I had to go in and OPT IN for anniversary gifts. I wondered why I never got any for 7+ years. Year 8 is due next month. Hopefully I'll get my 1 PPV or 3 months of the game channel.