A few days ago, I bought an Oushui LGP999 mobile phone online, but I couldn't get the card, but I entered the settings and saw that the operator showed that it was Unicom.
You bought the American version of custom machine, and the full model name should be LGP99G2X. This version of the machine is locked with a PIN code, which means that the network of other countries knows nothing except that you insert a SIM card in the United States. You need a tool to open it. Either send it back or find a professional mobile phone store to unlock it.