Meaning fake software, that promises to do something, but it doesn't. FYI where "snake-oil" comes from...
https://en.wikipedia.org/wiki/Snake_oil
SMSs are all stored in a single database file in /system, so if an SMS(a record) is deleted from the database file,
it's gone forever. It's not like doing undelete on a PC, where it's only changing something in the directory that tells Windows a file is deleted, but the file data is still there until overwritten.