Try going on line to your phone company's or cable provider's website and go to "call blocking". I have 16 phone numbers so far on mine and can register up to 30.
I contacted my cable company as I have digital phone service and set up a call blocking account. It works but the only problem is these crooks have a huge bank of #s they use. If they can't get through with one number they use another figuring you can't block them all. As you say its good for about 30 #s. I think I'm close to that now. I know one thing. They will never get to talk to me as I have been phone smart for quite some time. If I don't recognize the # I will not answer. If its an important non solicitation call, they leave a message or I screen the calls. The DNC list doesn't work for charities surveys or political calls or calls out side the US.
I got a call from this number 253-245-4798 and caller was female. They said that my credit card was going to be cancelled with a limit of $3000.00 because I had too many credit cards I tried calling the number back and it said that the person requested not to be called back.