Help to unlock iphone7 ?

flourier

    I purchased iPhone 7 (T-mobile) from my friend in US and I planed to use it in CHINA one month ago.However when I went back CHINA and activated it, I found it got an error code that states, "SIM Not Valid." I thought it may due to the lock of the network,could you help me unlock it?

     

    IMEI:   XXXXXXXXXXXXXXX

    SN:  XXXXXXXX

     

    Your selfless aid and assistance will be highly appreciated.Thank you.

     

     

    *edited to remove personal information - Marissa

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