iPhone 6 Plus unlock error says try again later

Family member broke the glass on an iphone said if I could fix it I could have it which I did fix it. He bought a brand new phone from ATT and gave me the old one. I tried to unlock the phone online and like a million other people it just says can't process try again later. I just want the phone unlocked so I can use it with my carrier which is fair seeing as I know he paid for it and the new phone. Is there anyone that can help? It is frustrating when the stores say go online and use the form and then the form says sorry try again later. I am really frustrated at this point.