The other party can receive the text message, but call them and tell them that the phone is turned off.

1. When the other party turns off the phone, you can receive the message when you turn it on.

2. Your phone number is set on the other party's phone. When you dial his phone, there will be various prompts (depending on how he sets it, it may be busy, it may be turned off, or it may be out of service). In this case, you can try to dial another phone.