Send a text message to a foreign mobile phone, why can't the other party receive it?

I'm familiar with mobile phones, let me tell you:

Cost: China Mobile customers send point-to-point short messages to operators outside Chinese mainland, China, each 1 yuan; Receiving text messages is free.

International Peer-to-Peer SMS: Select Edit SMS on the mobile phone menu, enter the information content, then select Send SMS, enter the international code (00 or+)+country code+mobile phone number of the receiver, and then send it.

Upstairs, I disagree. In fact, this is really related to other international operators. China Mobile is from China, not covering the whole world. If there is a problem with the SMS gateway in the United States or the connection with China Mobile, it is not only the problem of our domestic operators! Whether to recover the responsibility of others! Compared with Unicom, I am already satisfied. Without Unicom, I don't want to use my mobile phone!