[celltellpb]

I want to unlock the booloader of a Mi8 lite in the Chinese version to write a global rom. I bought the activation, bought 25 credits, but when trying to unlock I get the error message described in the image.
I need help, because the client's cell phone was unlocked and with a global ROM and I ended up blocking his bootloader to write a more updated Global rom, so I bought this activation with such urgency.
Note: I've downgraded to MIUI 9.

Thank you very much in advance