Simple and quick.
Romans 6:7
The Watchtower uses it to claim a person who dies has paid for his sins.
Where does that leave the new covenant and Jesus' sacrifice which Matthew 26:28 says paid for our sins?
Acts 5:31 says that God exalted Jesus to His right hand for the forgiveness of sins.
If our death pays for our sins then there was no need for Jesus to die for us.
Also Romans 6:1-14 has nothing to do with our death paying for our sins.
Romans 6:1-14 describes the new life a believer experinces in Christ.