Who is responsible for a debt if the credit card company of the deceased turns the unpaid balance to the collection agency for the family to pay but there is no spouse or children?

If there is no inheirator of the deceased's estate no one is responsible. However if you have inheireted the decease estate and accepted that then you also have to accept the debt. Payment of debt should come from the estate of the deceased. If the estate of the deceased is without sufficient resources to pay the debts and the deceased does not have joint obligation with anyone, the total of debt should be added together and the estate should be divided equally among the debts. If anything is left after paying all debts of the deceased, the remaining resources can be divided among suvivors or beneficiaries.