I have an iphone 6s bought Oct2016 in US (new brand, unlocked) which has been working well until a couple of days ago when I had to change the operator. The phone has been in used in Argentina.
After inserting a new sim (different operator) the device is not able to be activated.
I tried everything (restoring, changing appleid, turning off find my phone, erasing the phone in icloud/appleid, etc.)without success. I finally decided to run a simdoctor test and I received a report saying that Verizon Wireless reported the phone in a blacklist as stolen in Nov-2016. I really appreciate your help to unlocked the mobile phone.
Federico
PS: I can provide doctorsim report and purchase ticket if necessary.