Here is the one scripture that should stop the Jehovah Witnesses, Seventh Day Adventists, Messianic Jews, Christadelphians, and any religion who say people do not go to heaven.
Matthew 23:13 “Woe to you, teachers of the law and Pharisees, you hypocrites! You shut off the kingdom of heaven in men's faces. You yourselves do not enter, nor will you let those enter who are trying to.
There are other false doctrines in those religions, but that one scripture should be enough to stop any further involvement.
So which of those denominations are you getting your false beliefs from about the spirits of humans?