Allied Interstate harassment

my husbands ex-wife owes a debt and Allied Interstate has been calling my unlisted phone number daily harassing me for a debt owed by Cynthia Elizondo who has never lived at my addressed nor has my private unlisted phone number ever been hers as a number given as a valid number for her to be accessed at. Never the less they have been ceaselessly calling me stating that this is the number that she gave them for them to reach her and call daily. How do I get this to stop?