Deceased, But Still Expecting Family To Pay

How do I get cable company to realize my sister in law is deceased.  She owed money, but there was no money to pay them. She died intestate. My husband and I wanted to purchase cable for my daughter who is now living in the same house.  They stated that until the bill is paid, they are not putting cable in the home.  My husband and I have had cable for many years. We pay the bill, but are currently considering changing our provider.