I search all box unlocking, no any box can repair IMEI with new security, Now all unlock are at risk when erase phone without back up, or if phone corrupt EFS or modem and become network not registered no one can repair. All certificate wrote from server have been caught by service provider because it appear 3 to 4 times One IMEI many user, so Network Provider drop the signal.
In Tanzania change IMEI has been restricted but repair IMEI authorised, most of phone unlocker/repair re-write certificate, and QCN S/No. become unknown though it seemed as fake phone.
Please Z3X Team work for repair imei and s/no. it will help. even at cost.