Sending a message can still show success. Was it hacked?

Whether to enter the blacklist is related to the communication software downloaded by the other party's mobile phone or the blacklist function of the other party's mobile phone. Some software and mobile phone functions can receive short messages with blacklisted numbers even if the numbers are blacklisted, but the short messages are saved in the blacklisted software, not directly displayed in the mobile phone, while some mobile phone blacklisting software and mobile phone functions directly block short messages with blacklisted numbers, so it depends on the function of the other party's communication software or the blacklist function of the mobile phone.