online. >> i haven't slept for the last week thinking if my phone has >> reporter: lacy says she sold her old phone to a company who promised to wipe all her old data. >> at the time, 120 bucks cash and i bought a new phone with the upgrade. it was a good deal. >> but when he bought a new phone off ebay -- >> 13,000 text messages on it. hundreds of e-mail messages. >> 120 bucks t or >> 1e lbucks t or >> reporter: a common mistake it c to wiping your it cit buiping your we wanted to see what that would do, so we reset our producer's old iphone 3g. this looks like a whole new phone. besafe, man deletany text messages >> now we'll see if we can bri >> reporter: and with a little digging, we find all of her original information stl 2,000888 photos extracted. >> yeah. >> so, how do you protect