I had someone come by to look at my iPhone, they said they just wanted to come look at it. Well, they ended up wanting to buy it on the spot. I went into my settings and clicked erase all content and settings and proceeded to hand them the iPhone. They called me about an hour later and said my pin was still on the phone and asked for it. This was my first indication that the phone had, in fact, not erased all the data. I went onto iCloud, it could not detect my location but it could detect an iPhone, except the name on it had been changed to the buyers. I was able to select erase all data and it stated it would be erased when the phone is turned back on. My question is how can I be sure that this will work? Is there the possibility that this person has figured out a way to bypass the erase? Thanks.