mak0t0 wrote:
I have a iPhone 5 that was enable using AT&T as the service. I'm giving the phone to a person that has Verizon as a carrier. Will the phone work on their service provider?
No. Verizon will not activate an iPhone not sold specifically for them on their network. The new owner should be able to use a pre-activated LTE sim card from Verizon in the iPhone assuming the iPhone has been unlocked by AT&T. But will not have access to Verizon's CDMA network in areas where LTE is not available.
mak0t0 wrote:
What is the difference inside the phone that it won't work?
No difference. The Hardware is the same. Its Verizon that is the issue.
mak0t0 wrote:
Why doesn't Apple just sell unlocked phones?
They do. They have unlocked Phones for sale in any Apple Store, and through the Online Apple Store.
mak0t0 wrote:
I also tried to wipe my phone clean of all content, but for some reason not all of my contacts can be deleted.
How did you try to wipe it clean?
Follow these directions:
What to do before selling or giving away your iPhone, iPad, or iPod touch - Apple Support