Just disconnect your landline, (if you can) stop paying for people to bug you. The phone companys of old are loosing to the cellphone computer age. In 20 years or less no one will know what a landline is/was.
Calls several times a day, then after 8 at night. ID says FAV. Never answer when I do not know who is calling. If it is so important, leave a message, otherwise QUIT CALLING!