Can I type it out in the business hall after deleting the sent SMS?

You can't. Business hall operators only provide channels. According to the national communication user information confidentiality regulations, operators only keep the call or sending time of telephone calls and short messages, but not the call content and short message content. If there is particularly important news, involving economic or even criminal cases, you can report the case and see if there are other ways to deal with it through the public security organs.