What is "The Apostolic Teaching" that Voice of Elijah claims was lost?

[Another user](https://christianity.stackexchange.com/users/123855) posted a link to a group calling themselves the "Voice of Elijah". On the surface, they appear to be a not-obviously-remarkable Christian group aside from frequently referring to something they call "The Apostolic Teaching", which they claim was "long since lost by the Church" but "is once again available to those with ears to hear". However, it is not at all obvious from their site what this teaching *is*. What is this teaching? Does it differ from mainstream Christianity, and if so, in what way?