"God Told me" issue

The Bible listed people who were able to hear God. Moses did but others didn't as Hebrews 1:1 said "In the past God spoke to our forefathers through the prophets at many times and in various ways." The Apostles did but many others didn't, in Revelation was the last known biblical "God told me" from John. Only one time God really opened up to everyone is when Jesus was baptized. Matthew 3:17 And a voice from heaven said, "This is my Son, whom I love; with him I am well pleased." Speaking directly from God is an interesting concept. The Bible listed very little on what to do if we ever heard God. How did anyone handled when the cults such as the Mormons who told others "God told me"? This "God told me" is walking on thin ice and playing with fire. This is where I am having problems with some Christians who are so big on "GOD SPOKE TO ME" which are trying replace the authority of God's word. I rather follow God's Word than man saying "God spoke to me".