The phone was intercepted and the SMS showed that it had been sent to the other party.

I do not see any at all. According to the query of Zhongguancun online website, the hacked mobile phone number can still send messages to the other party, but the short message will not appear in the inbox, but will be blocked by the system in the blacklist short message list, so the other party can't see the sent message, and even after sending it, it shows that it was sent successfully. The success here means that the operator sent the SMS, and the other party's mobile phone successfully received the SMS, but it was not the other party who checked the SMS.