Unlocked my iphone 4

Hello friends of apple, my question is this, I buy a phone from AT & T in the U.S., becauseunfortunately for things beyond my control I had to leave the country, reporting to AT & T,then they said they would report to apple for me, finally reported they already sent me theproper authorization to unlock my iphone 4, told me to do a backup and restored onceitune and my iphone is activated for any company in Nicaragua