How to send a large number of advertising messages without being locked by mobile operators?

You have to tell the client not to report it. Mobile companies will only lock their phones if they receive a certain number of reports, and it doesn't matter how many messages they send a day if they don't receive reports.

The same was true of QQ home improvement consultants before. When it sends a text message, it will add something like don't report it, but it seems that someone still reports it, so now it only sends a few messages a month.

This situation requires you to communicate with your customers yourself.