If you have all the answers.
And you know that someone else doesn't.
Make sure you understand that love is the answer.
If you need to call someone a heretic or false teacher... or if you need to call a group a cult...
Please do so with love.
Otherwise it seems you are at risk of not being a true child of God:
1 John 3:10 (NIV)
"This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not God’s child, nor is anyone who does not love their brother and sister."1 John 2:9 (NIV)
"Anyone who claims to be in the light but hates a brother or sister is still in the darkness."
1 John 4:7-8 (NIV)
"Dear friends, let us love one another, for love comes from God. Everyone who loves has been born of God and knows God. Whoever does not love does not know God, because God is love. "And this lines up with Jesus' words in John 13:34-35 (NIV):
“A new command I give you: Love one another. As I have loved you, so you must love one another. By this everyone will know that you are my disciples, if you love one another.”