Have you ever play the game chess? People think the game Chess is a toy, but it's not. Chess is a thinking mans game. If God, the designer of this game, knows which musician will be crowned king in the end, if He has called, appointed and anointed you to play and is using you to be an instrument to do His will, why in the world would you allow the devil to chase you away from your post.
(The only way any king can be dethrowned or step down from his post is if he is found gulity of treason and that's not the case here)
Of course the devil can clearly see which direction you are headed in the music ministry and so he uses the tackiest weapon as ever, an ameture pawn of all people to move you away from your post. You are probably a few inches away from being crowned King (promoted to a higher level in the music ministry), and the devil is doing everything in his power to block it. I know this must be hard for you, but something like that will cause me to persevere more.
One way or another the people or person that appointed the other guy as the pastor musician will wake up and realize they moved the wrong man in position.
So I would encourage you to hang in there the game is not over, yet. Show this guy that God is moving you in the right direction. If God says that post belong to you, then be prepared to stand on it.