I bought iPhone x and iPhone 8 via T-mobile. And I want to use iPhone X in different country, so I asked t-mobile how to unlock my iPhone x, then they said your phone has to be full paid. So I shipped my phone to my mom, and paid then ask. But, they just said your phone can't be unlocked because phone was not used in US. I'm so frustrated. Is it my fault? nobody told me about that even t-mobile assistant. How can I unlock my iPhone and use the phone in my country? T-mobile said we can't, and even apple in my country said we can't cause locked by T-mobile. What should I do?