How Accurate is ListSource???

[Nechole Thompson]

Hello BP Members

I'm new to BP and today will be my first step to Wholesaling and start my  marketing campaign. This morning i decided to buy a list of absentee owners from ListSource and I'm wondering how accurate is it. The first  few property addresses (according to Zillow and Truila)  were sold a year ago. How can I make sure that the properties have not been sold before I start my direct mail campaign???