How do these shaykhs who mention details of the unseen operate, and is this permissible in Islam, or is it dealing with jinn?

Claiming knowledge of the unseen (Ghaib), secrets, and the future is an act of divination (kahānah) that expels its perpetrator from the fold of Islam. What the questioner mentioned about the state of the aforementioned shaykhs is from the whisperings of the devils (shayāṭīn), as they eavesdrop on the heavens and then lie a hundred lies along with what they heard. There is no educational course that qualifies one to know the unseen. And whoever approaches diviners and believes them, thinking they possess knowledge of the unseen, has committed an act of disbelief (kufr) that expels them from the fold of Islam. And whoever approaches them merely to ask questions, without believing them, has committed a major sin (kabīrah) and will have the reward of their prayers withheld for forty days. The exegetes mentioned that the jinn's enjoyment of humans occurs through the jinn informing them of unseen matters or fabricating lies. Most of those who deal with jinn are far from guidance, commit major sins, extort money, and practice sorcery.