Device Unlock Portal failed
In 2013 I paid full price for a Samsung Galaxy S2 (SGH-i727) phone, and selected a monthly plan, at an AT&T store. Less then a year later I changed to GoPhone pre-paid service. I was assured that the phone was mine without any encumbrance. I used GoPhone for a couple of years. A few months ago I switched to a different carrier. I just gave that phone to a friend. She went to use it with t-Mobile and found it was locked. She visited a store, but they said they could not help her. They suggested she use the ATT.com/deviceunlock website. But when we tried the website we got "Your data cannot be validated by the system." We tried getting through to customer service, but was blocked because the phone is no longer an active phone.
My friend wants to file a complaint with the FTC. But I convinced her to let me try to communicate with this forum before she takes that step. I see her point. Someone that outright owns a phone and owes nothing to any service provider should have easy access to an unlock code. How should I proceed? THANK YOU!