I heard in the name of the Gr”a (Vilna Gaon) that after hearing of a mekubal that knew private things of peole that came to him, he asked that the mekubal be brought to him. He came and told the Gr”a personal information about him (the Gr”a) After spekaing with him for a while, he told his talmidim to chase him out of town. Reason being that there are two ways this “mekubal” could know these things, through Koach haKedusah and koach hatumah. After speaking with him (in learning) the Gr”a said his abilities do not come from Koach HaKedusha. Therefore he needs to be chased out of town.
I second what dveykus613 said. Read R’ Yaakov Hillel’s book Faith and Folly, or ???? ???? in Hebrew. He is a mekubal that is mekubal by all of the Litvishe/Ashknenazic Poskim. In his book he says to be careful of all these so called mekubalim.
He brings a story of someone that was engaged and went to a mekubal for ????. The mekubal told him his name doesnt match with the kallah’s- whatever that means- and he should immediately break the shidduch. Choson goes crying to the Steipler asking what to do. The Steipler who was known to never get angry became visibly angry/upsent and said to ignore this advice and gave his brocho to the chosson.