The Mississippi Public Service Commission has created an app that will allow you to stop telemarketer calls by registering for the Mississippi No Call List.
If, after you have signed up for the list, a telemarketer still calls you, the app allows you to block their number and report them for violating the Mississippi Telephone Solicitation Act.

Though the app is made for apple or android mobile phones, you can still register landline phones through the app as well.
To download the app, search PSC No-Call Mobile Application on the app store. If you want to sign up for the No Call List without downloading the app, you can also register online here.
https://www.psc.state.ms.us/nocall/subscriber.aspx