We can not, and should not use the excuse that the Bible has been added and changed to ignore the word of God.  We need to study and show ourselves approved to the Lord.  We can not and should not justify this to continue in our sins but I will say this.  Adam and Eve only really had one rule to follow and they couldn't do that, it is by grace that we are saved

Revelation 22:19 And if anyone takes words away from this scroll of prophecy, God will take away from that person any share in the tree of life and in the Holy City, which are described in this scroll.