The iPhone 6 arrived and I built it with all my data. 12 hours later it overheated and completely died. They want me to return it 'as is' to get a refund; however, it now contains ALL MY PERSONAL DATA. As they then sell off broken phones to an unknown third party and specifically offer no protection for whatever happens to the data, I'm in a dilemma. If I physically remove the memory it voids the guarantee. There is no other way to wipe/reset it, since it's broken. I might be paranoid about identity theft, but Apple recommend never returning a phone without wiping the memory. And Gazelle's own terms spells out that they take zero responsibility for what happens to your data once they sell it on.
Apple specifically address this and guarantee the security of any phone data returned to them - whereas Gazelle gives no guarantee of this and specifically warn buyers that they will sell the phone on to an unknown recycler.