Cavalry Investments, LLC Debt Collection Complaint

Cavalry Investments, LLC Debt collection department,

Credit card Communication tactics Frequent or repeated calls Nevada

There is a certain debt collector known as - - - that is repeatedly calling and harassing my poor old - year old grandmother on the basis of a debt I DO NOT legally owe. I am a resident of -, where the debt should have expired last year, yet they call her at her number in -, where I do not know how they got that number, as I have had no communications with them. What actions should I take to assert my rights and my grandmother 's privacy?