I bought this iphone 4s off craiglist a couple months back and now ive started messing with it, i put the meid in the the checkesnfree.com

and i get the report back

carrier sprint---stolenesn

carrier ncis----Cleanesn

carrier mystolenphone.com----cleanesn

how do i know if its a good esn or a bad esn with these results? is there anything i can do with a bad esn iphone.. thanks