Looks like you haven't paid off your device yet. Follow these steps to pay off your installment plan
Dear friends or AT&T Customer Service,
I have got an iPhone 6s from USA whose my sister brought to Brazil. In USA it worked well with AT&T sim card, but I am trying to unlock it and failed miserably all the time. When I try to use the AT&T webpage there is the message: "Looks like you haven't paid off your device yet. Follow these steps to pay off your installment plan. Then, wait 48 hours before you submit a new request."
But there is no installment plan to pay off, no debits, anything linked to the IMEI of the device when used in USA. It was used for my sister for years! Now, just because she gave me the phone and I am trying to use it, I cannot due to this message. At Apple Store they told to solve with AT&T. I am trying to contact AT&T, but there is no way, no support by chat unless I have a phone number, not email, and to call from here will cost a fortune! I read in many forums that this is commom to happen with many AT&T customers and even others carriers. And, worse.... AT&T does nothing to help.
May, someone, please help me solve this problem? How can I unlock my iPhone from Brazil? Or, may someone send me an email to contact Customer Service or someone who can help me? Thanks in advance.