Hey there, magenta1989407! We definitely want to help you get to the bottom of this! Did you have a chance to take a look at the unlock requirements in the link that snn_555 shared? I noticed that you mentioned that your device had to be replaced last year -- did you use it with T-Mobile after the replacement? Did the replacement happen through T-Mobile's supplemental warranty program, or did you have the device replaced by the insurance agency or by Apple directly?