Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils. 1 Tim. 4:1.
Do you believe that you should judge the Bible by your experience or that you should judge your experience by the Bible? When something has happened to you, when you have experienced something, it is very difficult not believe in it. It's hard not to accept something you have experienced as real. And yet our own experience by itself is not a safe guide, in spite of how real and valid and convincing it may seem to us.
When Saul sought out the witch of Endor to learn what would happen at the battle that he was about to engage in, he experienced something real. Not only that, but the prediction that he was given in that setting, by the spirit posing as Samuel, proved to be correct. But that did not mean that it was from God.
Satan "will present his temptations to men in a manner to pervert the senses of all who are not shielded by divine power."--The Great Controversy, p. 554. In the end of time, we are told that miracles will be performed, that the sick will be healed. Satan is a real being, and the works that he does are real also. It is true that there are many hoaxes performed by magicians and others, who can make it appear as if things are happening that actually are not. But even if you could prove the absence of hoax, and the presence of the supernatural, that does not prove the supernatural to be of God.
It is when truth is mixed with error that it is the most dangerous. If there is a brown jar that contains poison, with a skull and crossbones on the label, clearly marking it poison, will it be as dangerous as poison in a green bottle marked "7-up"? Satan knows better than to come openly with his devices. He knows that the best lies are those that are only partly untrue. He knows that the best way to reach people with his power is to come disguised in such a way as to appear as an angel of light. It is then that we are more ready to accept his devices.
It is only in dependence upon Christ, in acquaintance and friendship with Him through an ongoing relationship based on His Word, that we can be secure against the devices of Satan.